Faith Simplified: What We Believe and Why We Believe It

by Aaron Armstrong

Curiosity A Clear and Concise Explanation of Christianity

The Christian faith has incredible life-changing power. And yet too many people—Christians included—know too little about it. The more we truly come to know God, his words, and his works, the more our lives become ripe for transformation.

With practical teaching and relatable storytelling, Faith Simplified unpacks the faith-defining truths of Christianity and their profound bearing on how you live each day. Addressing the curious, the questioning, and the committed alike, author Aaron Armstrong draws on biblical knowledge and centuries of Christian theology to cast light on the faith’s potential to powerfully affect your life.

With abundant insights and engaging discussion questions in every chapter, Faith Simplified will inspire both individuals and groups to embrace faith in fresh, compelling ways. This accessible guide will help you take these truths to heart so you can understand and experience the blessings of Christianity at their fullest.

Genres: Nonfiction, Christian

288 pages, Paperback

First published May 1, 2025

Reviews

[Maven_Reads · Rating 4 out of 5]

Faith Simplified: What We Believe and Why We Believe It by Aaron Armstrong

Faith Simplified is an accessible, contemporary Christian theology guide that answers foundational questions about the Christian faith in clear, conversational language: what Christians believe, why it matters, and how those beliefs shape daily life. Aaron Armstrong draws on biblical teaching and centuries of theological insight to unpack core doctrines like the nature of God, Scripture, the gospel, human purpose, and the Christian worldview, aiming to make even complex ideas understandable without dumbing them down. It includes practical teaching, relatable stories, and reflection questions at the end of each chapter designed for personal growth or group discussion. This book is written for people who are curious about Christianity, new believers, and longtime followers seeking fresh clarity and conviction about their faith.

I came away feeling strengthened and encouraged by how Armstrong explains timeless truths with warmth and clarity, making Scripture’s central claims feel both intellectually solid and personally life‑changing. The discussion questions helped me slow down and internalize key ideas instead of just reading them. Whether you’re exploring Christianity for the first time or wanting to deepen your devotion, this book felt like a welcoming, faithful companion on that journey.

Rating: 4 out of 5, for its engaging clarity and heartfelt, Scripture‑rooted encouragement.

[Jared Baergen · Rating 5 out of 5]

Something happened as I read this book: I couldn’t put it down. I finished it in five hours because of how wonderful “Faith Simplified” by Aaron Armstrong truly is. I read a lot of theology, including Bavinck, Turretin, Mastrict, Beeke, Vos, Fesko, Wellum, Swain, Duby, Horton, etc. I am also always on the lookout for a short theology book that I can use to supplement my middle school Bible classes. Armstrong literally hit a grand slam in my opinion. Clear, concise, practical, entertaining, engaging, and relatable without difficult vocabulary or minimizing tough theological concepts. People usually go with Grudem’s 20 basic truths of the Christian faith or Horton’s Core Christianity. “Faith Simplified” is my new favorite by a long shot. Thanks, Aaron!

[Sally Matheny · Rating 5 out of 5]

I am not an academically trained Biblical scholar, but as a Bible-believing Christian, I read books with a critical eye in search of anything that doesn’t line up with God’s Holy Word. Faith Simplified is embedded with Scripture, and the author writes with a Biblical worldview. I recommend it for adults new to the Christian faith and those curious to learn more.

I like how Armstrong introduces a theological term, what some call a “church” word, and then he proceeds to explain it in layman’s terms.

One example is from page 233:

“The Lord’s Supper: Also called communion or the Eucharist, the Lord’s Supper is a sacrament for all who believe, all who have been saved through faith in Jesus’ death and resurrection.”
He expands on concepts like this in further detail by pointing readers to what the Bible says. Sometimes Armstrong mentions what his knowledge, or lack thereof, about a concept was before he was saved and what he has learned since. His writing style has an engaging conversational tone.

Each chapter ends with 3 – 5 questions for readers to ponder.

Also, I appreciate the format of the book. Readers can open it to any section to learn more about certain topics. While it may be helpful, the chapters do not necessarily have to be read in consecutive order.

[Jordan Shelvock · Rating 5 out of 5]

This is a really helpful book for a new believer in Christianity.

When I was a new Christian involved in a college campus ministry, I was exposed to a lot of ideas from various Christians emphasizing different aspects of the faith. This book would have saved me a lot of time and kickstarted my journey to faithfulness by really focusing on the basic yet foundational beliefs that are important.

Armstrong is an excellent guide who has a very simple way of explaining complex truths. His tone is even light and fun.

He walks us through basic topics like who God is, how he revealed himself, creation, and continues all the way until the end and a brief discussion on the millennium (and more importantly on the agreed basics of Christian eschatology).

New Christians are often overwhelmed with all the information they could begin trying to explore. This provides a good survey of the important bits and is a great launching pad for new believers to begin a lifelong pursuit of exploring these same topics in greater detail.

[Kevin Larson · Rating 5 out of 5]

fantastic introductory theology

This is an excellent introductory theology that also has an apologetics emphasis. The author does a good job of touching on most every doctrine while anticipating and answering questions you may have. I think this is a really fantastic resource.

[Will Dickerson · Rating 5 out of 5]

When I was in graduate school, I had a professor who was widely respected in his field, but who despised writing of the verbose and pedantic nature. Once, half-jokingly — but only half — he said he believed verbosity was the unforgivable sin against the Holy Spirit. If a student delivered a particularly good seminar paper, Prof Tierney would put the tips of his fingers together, stare at some point where the wall met the ceiling, and say, "Well . . . that was very concise." This was a compliment of the very highest degree. When Prof. Tierney said a paper was "concise," he meant that it clearly expressed the essence of a complex matter in language that even a non-specialist could understand, and it did so with an economy of words.

When I was in seminary, I sometimes encountered theologians who relished discussions of arcane points of theology 'ad infinitum' in academic language that only a select few could understand. Aaron Armstrong's book "Faith Simplified" is not of this nature. Rather, it is . . . concise.

[Klaudia Maciejowski · Rating 5 out of 5]

I won this through the Goodreads giveaway and I’m so happy I did. I had a great time reading, taking notes, and using its content in conversations. Such a great book for people of all walks of faith.

[Joshua Chatman]

4.3
It’s an edifying read. It’s a good resource to give to a new Christian.

[Aaron · Rating 5 out of 5]

In Faith Simplified, Aaron Armstrong explains what we believe and why we believe it.



A Friendly Tour

This book takes you on a tour of Christian doctrine. Armstrong writes in simple and straightforward language without watering down the truth.

The chapters are similar to what you would find in a systematic theology: God Is (attributes of God), God Speaks (the Bible), and God Reigns (eschatology) are some examples. But Armstrong writes in a way that feels like a friend simply talking to you about his faith.



Providence and the Incarnation

I was most pleased to read about God’s providence—a somewhat difficult doctrine made clear as Armstrong explains how God’s plans for the world go forward through the actions and choices of human beings. I marveled at the fact that God is actively engaged in every moment.

Surprisingly, I was satisfied to read Armstrong’s honesty in embracing the mystery of the incarnation. It is a strange thing! But it is beautiful and good news for those who believe it. Armstrong does not encourage blind faith—but rather giving time to fall in love with God.



Strengthen Your Belief

This book is for those who are curious about Christianity. It is for new believers who want to jump-start their journey with Jesus. It is for seasoned saints who want to gain some fresh perspective on timeless truths.

Faith Simplified does not mean walking away with a weaker faith. Instead, it will strengthen you as you set your gaze upon the glory of God.



I received a media copy of Faith Simplified and this is my honest review.

[Nitoy Gonzales · Rating 4 out of 5]

Aaron Armstrong took on something essential but complicated thing that is important not just for Christians (new and seasoned) but also for those curios about Christianity. Telling what we believe is a HUGE task. The author even struggle with a "push and pull", on sharing everything and what the readers should read. There are lots of thing that should be said about our faith however the book sticks with what is the basic. Faith Simplified is for those who want to read a book on systematic theology but felt bogged down to even try. The book is both interesting and engaging which is good to keep readers on their feet. I have read a lot of books on doctrine and I wont throw the towel and say "their is nothing new in this book". Armstrong gives some fresh take on tackling the usual Christian doctrine and injects some new insights that I haven't encountered yet that gives you that "light bulb" moment. As you read further, the book turns into an apologetics book. So a mix of doctrine and apologetics that will convince the readers that our beliefs is crucially important here and in eternity. What makes me a bit hesitant to score this one a 5, is that it's a bit long for unbelievers. So I have to remind myself that the word "simplified" on the title doesn't mean a slim book but an accessible and easy to understand book. Nevertheless, a good book that you should consider picking up.

[Amber Ginter Johnson · Rating 5 out of 5]

Faith Simplified is exactly what its title promises—a clear, compassionate, and deeply biblical look at what it really means to follow Jesus in a complicated world. Aaron Armstrong has a rare gift for taking rich theological truths and making them both understandable and personal. Rather than watering down the gospel, he brings it into focus, helping readers see that faith isn’t about adding more to our already overloaded lives—it’s about returning to the simple, steady center of Christ Himself.

I appreciated how Armstrong weaves together Scripture, story, and reflection in a way that feels both grounded and pastoral. Whether you’re new to Christianity or have walked with God for years, this book is a refreshing reminder that faith isn’t about striving harder but trusting deeper.

If you’ve ever felt like your spiritual life was “too complicated,” or that you were missing something essential in the middle of all the noise, Faith Simplified will help you breathe again. It’s an invitation back to the basics—in the best, most beautiful sense of the word.

[Diana Fletcher · Rating 5 out of 5]

Faith Simplified is exactly what its title promises a clear, down to earth walk through what Christians believe and why it matters. I really appreciated how Aaron Armstrong takes big, sometimes intimidating truths and makes them feel both understandable and personal.
What stood out most to me was the balance between solid biblical teaching and real-life stories. It never feels academic or preachy. Instead, it feels like sitting down with someone who genuinely wants to help you grow. The discussion questions at the end of each chapter are a nice bonus they really make you slow down and think.
Whether you’re new to the faith, curious about Christianity, or someone who’s been in church for years, this book gives you a fresh perspective on who God is and how knowing Him transforms everyday life. It’s uplifting, practical, and surprisingly moving. I’m glad I picked it up.

[Sara Dangerfield · Rating 5 out of 5]

“Where has this book been all these years?” This is what I kept asking myself as I read through this book. With each chapter I’d even look over at my husband and emphasize just how good this book was, and how grateful I was that it had been written.
The author does a phenomenal job of answering questions without making the reader feel dumb for asking them (whether publicly or not). His writing feels like the wisdom of a big brother, or father, who gently, yet boldly, walks you through the truths about God and Scripture, and how our lives are affected by them.
It’s a must read for everyone! Whether you claim to follow Jesus or not. Whether you’re inquisitive, curious, or just need a refresher.

[Aaron · Rating 5 out of 5]

As always, I'm admittedly biased, but I do hope that this book encourages everyone who reads it.

[Wendy Stover · Rating 5 out of 5]

I can't remember how this book ended up on my "to be read" shelf, but when I was able to get it through my library on the Libby app, I checked it out. I don't claim to know all things about the Bible. I have read it a few times cover to cover and I have been studying daily for several years now. I attend a Bible teaching church. I learned much from Faith Simplified. I am able to clarify things in my own heart, and when speaking to others, thanks to this book. I bought a physical copy of it to give to my son, who is in jail right now. I have been praying for years that he would turn to Jesus and in jail he started reading the Bible I sent with him. Now he is also reading Faith Simplified and it has helped bring greater understanding to him. I am so grateful for this book. I would recommend it to all new believers and the rest of us.

[Brad · Rating 5 out of 5]

I read Faith Simplified with a group of brothers, and it proved to be a really solid, discussion-worthy read. As the title suggests, the book does an excellent job of making core Christian beliefs clear and accessible without oversimplifying or watering them down.

The chapters are well organized, grounded in Scripture, and written in a pastoral, conversational tone that worked well for men at different stages of faith. The discussion questions helped move us beyond just reading into meaningful conversation about what we believe and why it matters in everyday life.

While it’s not a quick or lightweight read, the depth is a strength—it invites you to slow down and really engage. This isn’t a comprehensive systematic theology, but it’s an excellent foundation and refresher on the essentials.

I’d highly recommend Faith Simplified for small groups, new believers looking to establish a solid foundation, or longtime Christians who want to revisit the basics with clarity and purpose.