Now about what he commanded them to teach. After His resurrection, before He ascended, Jesus had just spent forty days under the new covenant teaching the Disciples. It is these teachings that He was referring to. These were the teachings of the new covenant. And it is these things that the Disciples then preached in Judea, Samaria, and to the ends of the earth. Before the crucifixion Jesus said in Matthew 10:5-6 KJV
[5] “These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not: [6] But go rather to the lost sheep of the house of Israel.”
After the resurrection He now sends them to Samaria and the whole world. Old covenant, law of Moses, Israel. New covenant, better promises, whole world.
Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity. Therefore whosoever heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock: And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock. And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand: And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it. — Matthew 7:21-27 KJV
I will simply reaffirm what I have said before, when you take the words of Jesus as the ultimate arbiter THEN read the letters of the apostles things are very clear. The issue is when one takes doctrine THEN frames the words of the apostles and THEN the words of Jesus within those doctrines all twisting is possible.
And Samuel said, Hath the LORD [as great] delight in burnt offerings and sacrifices, as in obeying the voice of the LORD? Behold, to obey [is] better than sacrifice, [and] to hearken than the fat of rams. For rebellion [is as] the sin of witchcraft, and stubbornness [is as] iniquity and idolatry. Because thou hast rejected the word of the LORD, he hath also rejected thee from [being] king. — 1 Samuel 15:22-23 KJV