We hold Christ's words as God's, and the Apostles' as breathed by God, but what Christian writings, next to these, could be more beneficial and instructive but the teachings of those who studied at the feet of the Apostles? It is from these that we can glimpse a picture of how the early Church was structured, and the doctrines of the Apostles which were not specifically enumerated in their Epistles. The fallibility of these documents is also striking, in that even though they come from a similar time to the Apostolic Epistles, they are evidently the works of men, not God.
"The heavens, as they revolve beneath His government, do so in quiet submission to Him. The day and the night run the course He has laid down for them, and neither of them interferes with the other. Sun, moon, and the starry choirs roll on in harmony at His command, none swerving for its appointed orbit." - Clement of Rome's Epistle to the Corinthians
"... Let us be earnestly, even passionately, eager to set about any kind of activity that is good. Even the Architect and Lord of the universe Himself takes a delight in working... Above all, with His own sacred and immaculate hands he fashioned man, who in virtue of his intelligence is the chiefest and greatest of all His works and the very likeness of His own image; for God said, Let us make man in our image and likeness; and God created man, male and female he created them... We see, then, that good works have not only embellished the lives of men, but are an adornment with which even the Lord has delighted to deck Himself; and therefore with such an example before us, let us spare not effort to obey His will, but put all our energies into the work of righteousness." - Clement of Rome's Epistle to the Corinthians
"By all means be pugnacious and hot-headed, my brothers, but about things that will lead to salvation. Just take a look at the sacred scriptures; they are the authentic voice of the Holy Spirit, and you know that they contain nothing that is contrary to justice, nor is anything in them falsified." - Clement of Rome's Epistle to the Corinthians
"It was in love that all God's chosen saints were made perfect; for without love nothing is pleasing to Him." - Clement of Rome's Epistle to the Corinthians
"That is why it is proper for your conduct and your practices to correspond closely with the mind of the bishop. And this, indeed, they are doing; your justly respected clergy, who are a credit to God, are attuned to their bishop like the strings of a harp, and the result is a hymn of praise to Jesus Christ from minds that are in unison, and affections that are in harmony. Pray, then, come and join this choir, every one of you; let there be a whole symphony of minds in concert; take the tone all together from God, ad sing aloud to the Father with one voice through Jesus Christ, so that He may hear you and know by your good works that you are indeed members of His Son's Body." - Ignatius of Antioch's Epistle to the Ephesians
"Faith is the beginning, and love is the end; and the union of the two together is God." - Ignatius of Antioch's Epistle to the Ephesians
"We have seen how former adherents of the ancient customs have since attained to a new hope; so that they have given up keeping the sabbath, and now order their lives by the Lord's Day instead (the Day when life first dawned for us, thanks to Him and His death)" - Ignatius of Antioch's Epistle to the Magnesians
"Certain people declared in my hearing, 'Unless I can find a thing in our ancient records, I refuse to believe it in the Gospel'; and when I assured them that it is indeed in the ancient scriptures, they retorted, 'That has got to be proved'. But for my part, my records are Jesus Christ; for me, the sacrosanct records are His cross and death and resurrection, and the faith that comes through Him. And it is by these, and by the help of your prayers, that I am hoping to be justified."- Ignatius of Antioch's Epistle to the Philadelphians
"They even absent themselves from the Eucharist and the public prayers, because they will not admit that the Eucharist is the self-same body of our Saviour Jesus Christ which suffered for our sins, and which the Father in His goodness afterwards raised up again." - Ignatius of Antioch's Epistle to the Smyrnaeans
"Abjure all factions, for they are the beginning of evils. Follow your bishop, every one of you, as obediently as Jesus Christ followed the Father. Obey your clergy too, as you would the Apostles; give your deacons the same reverence that you would to a command from God. Make sure that no step affecting the church is ever taken by anyone without the bishop's sanction. The sole Eucharist you should consider valid is one that is celebrated by the bishop himself, or by some person authorised by him." - Ignatius of Antioch's Epistle to the Smyrnaeans
"Whom no senses can reveal
Was for us made manifest;
Who no ache or pain can feel
Was for us by pain opprest;
Willing all thing to endure,
Our salvation to procure." - Ignatius of Antioch's Epistle to Polycarp
"To put it briefly, the relation of Christians to the world is that of a soul to the body. As the soul is diffused through every part of the body, so are Christians through all the cities of the world. The soul, too, inhabits the body, while at the same time forming no part of it; and Christians inhabit the world, but they are not part of the world. The soul, invisible herself, is immured within a visible body; so Christians can be recognised in the world, but their Christianity itself remains hidden from the eye... The soul, which is immortal, must dwell in a mortal tabernacle; and Christians, as they sojourn for a while in the midst of corruptibility here, look for incorruptibility in the heavens." - The Epistle to Diognetus
"You can see what He is saying there: 'It is not these sabbaths of the present age that I find acceptable, but the one of my own appointment: the one that, after I have set all things at rest, is to usher in the Eighth Day, the commencement of a new world.' (And we too rejoice in celebrating the eighth day; because that was when Jesus rose from the dead, and showed Himself again, and ascended into heaven.)" - The Epistle of Barnabas
"Never do away with an unborn child, or destroy it after its birth" - The Epistle of Barnabas
"The procedure for baptising is as follows. After rehearsing all the preliminaries, immerse in running water 'In the Name of the Father, and of the Son, and of the Holy Ghost'. If no running water is available, immerse in ordinary water. This should be cold if possible; otherwise warm. If neither is practicable, then sprinkle water three times on the head 'In the Name of the Father, and of the Son, and of the Holy Ghost'. Both baptiser and baptised ought to fast before the baptism, as well as any others who can do so; but the candidate himself should be told to keep a fast for a day or two beforehand." - The Didache
"Assemble on the Lord's Day, and break bread and offer the Eucharist; but first make confession of your faults, so that your sacrifice may be a pure one. Anyone who has a difference with his fellow is not to take part with you until they have been reconciled, so as to avoid any profanation of your sacrifice." - The Didache