The Epistle of Barnabas (not to be confused with the Gospel of Barnabas) was an early 1st century (80-120 A.D.) Christian document which was widely attributed to the apostle Barnabas. The Epistle of Barnabas was written to Gentile Christians and argues that Christians hold the true covenant with God (as opposed to the Jews of the time). This document is important because it reflects the views of the first generation of Christians after the apostles were no longer alive. We see in the writings of Eusebius that this document was widely accepted by the Christian church. This means that even if it was a forgery/false/gnostic document it still reflected the views of many early Christians.
As a side note, one really great thing about these types of documents is that no Christian has an unwaiverable dedication to forcing meaning out of the text. In other words, it would be much easier to convince a Christian of the plain meaning of the Epistle of Barnabas than anything in the Bible. In fact, it might benefit to have a discussion with someone about the meaning of example texts like this to then apply the same concepts to Biblical interpretation.
When I read early church documents the prime things I look for are “how do they believe one is saved”, “how do they treat Biblical interpretation”, and, most importantly, “what was their views about God.”
In regards to salvation, salvation to the author was salvation to the Kingdom of God. This salvation was contingent on not sinning. The Epistle of Barnabas seems to be immersed in the idea that sins separate individuals from salvation. A Christian who begins to sin is not saved:
Ye ought therefore to understand. Moreover I ask you this one thing besides, as being one of yourselves and loving you all in particular more than my own soul, to give heed to yourselves now, and not to liken yourselves to certain persons who pile up sin upon sin, saying that our covenant remains to them also.
The Lord judgeth the world without respect of persons; each man shall receive according to his deeds. If he be good, his righteousness shall go before him in the way; if he be evil, the recompense of his evil-doing is before him; lest perchance,
if we relax as men that are called, we should slumber over our sins, and the prince of evil receive power against us and thrust us out from the kingdom of the Lord.
For to this end the Lord endured to deliver His flesh unto corruption, that by the remission of sins we might be cleansed, which cleansing is through the blood of His sprinkling.
In the author’s understanding: people gave up sins, were washed by the blood of Jesus, but then could dirty themselves again if they fell away.
As to interpretation, the Epistle of Barnabas is entirely absurd when recounting the meaning of Old Testament texts:
For the scripture saith; And Abraham circumcised of his household eighteen males and three hundred. What then was the knowledge given unto him? Understand ye that He saith the eighteen first, and then after an interval three hundred In the eighteen ‘I’ stands for ten, ‘H’ for eight. Here thou hast JESUS (IHSOYS). And because the cross in the ‘T’ was to have grace, He saith also three hundred. So He revealeth Jesus in the two letters, and in the remaining one the cross.
In this passage, the author tries to draw an allusion to Jesus by the number of people circumcised. What is really awful about this is that the Old Testament was written in Hebrew, not Greek.
The Epistle of Barnabas heavily allegorizes the Old Testament texts, deciphering wholly boggling meanings. The author presumes that it is not a parallel or a lesson being drawn for modern audiences, but intended in the original writing of the text.
As to the author’s understanding of God, the text is fairly vague, which is a shame. The author does not seem to be gnostic, but might be a Platonist or disciple of Philo (as evidenced by his method of interpreting scriptures). The author does not exhibit a sense that mankind does not have free will or that God is outside of time. When the author talks about the future, it seems as if it would be like friends talking about future plans (not as time travel or prophecy):
We ought therefore to be very thankful unto the Lord, for that He both revealed unto us the past, and made us wise in the present, and as regards the future we are not without understanding.
When God is said to be eternal, it is in the context of time (not outside of time):
But let us pass on to another lesson and teaching. There are two ways of teaching and of power, the one of light and the other of darkness; and there is a great difference between the two ways. For on the one are stationed the light giving angels of God, on the other the angels of Satan.
And the one is the Lord from all eternity and unto all eternity, whereas the other is Lord of the season of iniquity that now is.
The author of the Epistle of Barnabas is not overtly Platonistic, although he might be.
One last note on the Epistle of Barnabas, it appeals that Christians should not practice abortion (this can be contrasted to Augustine’s moral acceptance of abortion):
Thou shalt not doubt whether a thing shall be or not be. Thou shalt not take the name of the Lord in vain. Thou shalt love thy neighbor more than thine own soul. Thou shalt not murder a child by abortion, nor again shalt thou kill it when it is born. Thou shalt not withhold thy hand from thy son or daughter, but from their youth thou shalt teach them the fear of God.