Show me where does Christ in the NT command that what He taught be written down so that we may believe.
He didn't. Because He was a Jew and He came neither to create a new religion, nor to ordain new Scripture. Nor did He ever command His disciples to preach and carry their ministry to the Gentiles! The Apostles decided to write the NT and to carry the Gospel to the Gentiles based on the fact that the Jews rejected Christ (cf Acts 13:46). Neither was Christ's teaching.
So why aren't you Jewish?
” Nor did He ever command His disciples to preach and carry their ministry to the Gentiles!”
You need to reread the gospels.
Mat 28:18-20, “And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth. Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, [even] unto the end of the world. Amen.”
“He didn’t. Because He was a Jew and He came neither to create a new religion, nor to ordain new Scripture”
Let me know if you want any more evidence.
Matt. 5:21-22, “Ye have heard that it was said by them of old time, Thou shalt not kill; and whosoever shall kill shall be in danger of the judgment: But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire.”
Matt.5:27-28, “Ye have heard that it was said by them of old time, Thou shalt not commit adultery: But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.”
Luke 5:36-38, “And he spake also a parable unto them; No man putteth a piece of a new garment upon an old; if otherwise, then both the new maketh a rent, and the piece that was taken out of the new agreeth not with the old.
37 And no man putteth new wine into old bottles; else the new wine will burst the bottles, and be spilled, and the bottles shall perish. But new wine must be put into new bottles; and both are preserved.”
Mat 26:28, “For this is my blood of the new testament, which is shed for many for the remission of sins.”