John records the words of Jesus in his gospel, chapter 14, verse 6. I am the way, the truth, and the life: no man cometh unto the Father, but by me. This establishes two things: Christ's divinity, and Christ's centrality to proper epistemology. The word "epistemology" derives from two Greek words: episteme and logos. Christ, in the first sentence of John's gospel, is identified as the Logos. Logos itself means many things. "Account" and "reason" are among them, but the King James Bible translates it as "word". Episteme is translated as "knowledge" or "understanding" and does not occur in the Bible. Epistemology then is an account or reason for knowledge or understanding, an answer to the question "How do we know?". The Stanford Encyclopedia of Philosophy claims that "epistemology seeks to understand one or another kind of cognitive success". Christ does not present a systematic epistemology in the way that philosophers generally expect it, but by exploring Christ's values and commands, one can be confidently synthesized.
From the opening verse, it is plain that Christ is bodily the expected epistemology of his disciple. The answer to the question "How do we know?" is "We know because Christ taught us.". That is not particularly fulfilling as an answer. It demands an answer to a further question: "What did Christ teach us?" In this question, the reason for this article begins to blossom. Christ, in his grand divinity, made this question very easy to answer. An answer recurs throughout all four gospels, and the variations on the answer are also each divinely instructive. As I hope to demonstrate, they depict and frame Christ's epistemology with a parsimony, consistency, and genius that cannot be adequately described with any adjective short of the honour implicit to "divine". It is perfect, even as your Father which is in heaven is perfect (Matthew 5:48).
The most universal ethical principle is known as "the golden rule", which is also known as the ethic of reciprocity. Being the most universal, it is also the weakest. Nevertheless, Jesus acknowledges it, recorded in Matthew's gospel, 7:12. Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets. As usual, he intensifies it, making it plain that all things are under its domain. Later, Christ uses the link of the law and the prophets to centre the greater Old Testament framing of the golden rule, and transition from the core ethic of reciprocity to greater teaching.
The greatest commandment of the Old Testament is centred by Jesus in all of the synoptic gospels. At the time of Christ's life, the golden rule was not understood to be supreme, especially in the Hebrew world. In verses 29 to 31 of chapter 12 of Mark's gospel, we read Christ framing the greatest commandment directly in the language of verse 5 of chapter 6 of Deuteronomy and verse 18 of chapter 19 of Leviticus. The first of all the commandments is, Hear, O Israel; The Lord our God is one Lord: And thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength: this is the first commandment. And the second is like, namely this, Thou shalt love thy neighbour as thyself. There is none other commandment greater than these.
There's a little aside here about translation intricacies. The Greek word "prote" translated as "first" also means "greatest". This is clearly a translation. In the original Hebrew, there are only three ways listed to love God. In the Greek, there are four. This is because the Greek is incapable of directly translating the original Hebrew. If you go by the King James translation (as you ought to), Jesus adds "with all your mind" here. The issue is that the third entry in the Hebrew is much more generic than the Greek permits. The Mechanical Translation translates that third term, "m'd", as "many" or "everything". Christ splits that into a combination of mind and strength. This does not reflect a Septuagint rendering! The Septuagint uses a three item rendering as well. Here, Christ relegates the golden rule to strictly second place.
Jesus reiterates this in Luke's gospel, chapter 10, verses 25 to 28. He ties compliance with this law in to eternal life. And, behold, a certain lawyer stood up, and tempted him, saying, Master, what shall I do to inherit eternal life? He said unto him, What is written in the law? how readest thou? And he answering said, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind; and thy neighbour as thyself. And he said unto him, Thou hast answered right: this do, and thou shalt live. Note that here, the response was given by a lawyer, and the lawyer's response is fourfold, reflecting the words of Jesus that I commented on earlier.
The final synoptic reiteration of this commandment comes from Matthew's gospel, 22:35-40. Then one of them, which was a lawyer, asked him a question, tempting him, and saying, Master, which is the great commandment in the law? Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it, Thou shalt love thy neighbour as thyself. On these two commandments hang all the law and the prophets. Interestingly, Matthew's record is threefold. The third item is "mind" here, unlike "strength", which is the King James and Septuagint rendering of Deuteronomy. This is important! Christ is implicitly teaching that the mind is greater than the strength here, despite other thoughts to the contrary. In this light, the King James rendering of the Deuteronomy passage should be revised. Finally, we see the law and the prophets re-emerge.
Using Matthew's references to the law and the prophets, a relation becomes plain. The golden rule is the law and the prophets, and it hangs from the two greatest commandments. The Greek word "krematai" translated as "hang" is also used to describe the criminals hanging on the crosses alongside Jesus. The implications here have many readings. One is that Christ's teaching is the superior implementation of the golden rule ethic. Another is that failure to connect the golden rule to Christ's superior implementation will hang you!
The central commanding verb—the Greek word "agape"—used in the greatest commandments is love. This is misleading in English because love in English has come to mean many things that are not implied by the Greek word. Agape is a God-like love that is distinct from romantic, friendly, and familial loves. The word itself is only weakly-attested in ancient Greek literature; it was popularized by Jesus. Christ's final reframing of the golden rule is to place himself at the centre. John's gospel records this, 13:34-35. A new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another. By this shall all men know that ye are my disciples, if ye have love one to another.
With that final passage, the thrust of this article completes. The divine epistemology of the Christ begins with the golden rule, grows in the law of the Old Testament, which is then interpreted truly by Jesus, and finally is supplanted by Christ's perfect example. Without it, a man is condemned to hang, and the wrath of God abideth on him. The only true form of cognitive success available to humanity is to acknowledge Christ's superiority as supreme arbiter of ethical behaviour. Everything else is subsequent.