One excellent piece of Christian doctrine which is not well-known today is the Didache. There is much to be learned from this historical Christian and Jewish document which was first developed in the couple centuries leading up to Christ's birth and was then added to by early Christ followers in the 1st and 2nd centuries.
In many ways it is similar to the 10 Commandments, but the Didache goes further and deeper than Moses' tablets. Many Christians (and non-Christians) today look at the Old Testament and the Commandments as so antiquated that they don't feel compelled to follow that instruction. However, the Didache is slightly more recent, and it incorporates the feelings and dogma of the main Christian leaders of the Apostolic era. As such, it is wise to follow.
Selected excerpts include:
"There are two ways, one of life and one of death, but a great difference between the two ways. The way of life, then, is this: First, you shall love God who made you; second, love your neighbor as yourself, and do not do to another what you would not want done to you. And of these sayings the teaching is this: Bless those who curse you, and pray for your enemies, and fast for those who persecute you. For what reward is there for loving those who love you? Do not the Gentiles do the same? But love those who hate you, and you shall not have an enemy.
...And the second commandment of the Teaching; You shall not commit murder, you shall not commit adultery, you shall not commit pederasty,* you shall not commit fornication, you shall not steal, you shall not practice magic, you shall not practice witchcraft, you shall not murder a child by abortion nor kill that which is born. You shall not covet the things of your neighbor, you shall not swear, you shall not bear false witness, you shall not speak evil, you shall bear no grudge. You shall not be double-minded nor double-tongued, for to be double-tongued is a snare of death. Your speech shall not be false, nor empty, but fulfilled by deed. You shall not be covetous, nor rapacious, nor a hypocrite, nor evil disposed, nor haughty. You shall not take evil counsel against your neighbor. You shall not hate any man; but some you shall reprove, and concerning some you shall pray, and some you shall love more than your own life."
*Writer's note: The definition of pederasty is the act of a man having "relations" with a boy. Thus the Didache is teaching to A) not conduct pedophilia, and B) forbid sodomy.
This document is more descriptive than the 10 Commandments in several ways. It is interesting, given the current social climate in the USA, that it specifically states do not conduct abortion. This is very clear; there is no second-guessing here. This, unlike today's political rhetoric.
The Didache is also emphatic and clear regarding paganism, witchcraft and the like. Practices like astrology, psychic-readings, and spirit conjuring are all unholy and lead to the path of Satan—and away from God.
As fallen people, it is very hard (maybe impossible) to truly follow all the teachings of the Didache. But it is a great teaching tool for teens, young adults, and others, in 2019 America.
–Ken Lambert has been writing for both secular and religious publications for several years. He co-authored the book Top 10 Most Influential Christians Since the Apostles and holds a Doctorate in Ministry. He resides in southern New Hampshire.