A Guide to the History and Literature of Judaism and Christianity. M. F. Eller, pp. 208, 209, in his book The Beginnings of the Christian Religion (New Haven, Conn.; 1958), "The act of emperor worship consisted in sprinkling a few grains of incense or a few drops of wine on an altar which stood before an image of the emperor. Perhaps at our long remove from the situation we see in the act nothing different from . . . lifting the hand in salute to the flag or to some distinguished ruler of state, an expression of courtesy, respect, and patriotism. Possibly a good many people in the first century felt just that way about it but not so the Christians. They viewed the whole matter as one of religious worship, acknowledging the emperor as a deity and therefore being disloyal to God and Christ, and they refused to do it.”Thus, those who took serious their stand as Christians during the first century and shortly afterward, refused to "repeat the oath of allegiance" to the emperor, and is "roughly equivalent today to refusing to salute the flag or repeat the oath of allegiance" today. These however, did pay to the government their "dues", taxes, tribute, fear and honor, but not allegiance. This alone is reserved for God, for Jesus told "Go away, Satan! For it is written, ‘It is Jehovah your God you must worship, and it is to him alone you must render sacred service.’”(Matt 4:10) 518 pages.
I actually only read about half of this. It was incredibly superficial, bolstered by large sections of Biblical text taken from their context and placed within the framework desired by the author, who only occasionally cited sources for where this external framework came from, while making stern claims regarding who wrote the books of the Bible and when with almost no citations. The further reading books at the end of each chapter might be interesting, if they were still in print, but a little of other books to read is not the same as writing an interesting, in-depth book of your own. I do not understand why books on Christianity or written from a Christian perspective think they can get away with being primarily just Biblical quotations, as if people studying Christianity do not have access to their own Bible and cannot simply go to referenced passages as easily or more so than any other citation. If you don't have anything to say, do not write a book.