Whatever it was, the consequences for not teaching it were severe.
Mark 8:38
38 Whosoever therefore shall be ashamed of me and of my words in this adulterous and sinful generation; of him also shall the Son of man be ashamed, when he cometh in the glory of his Father with the holy angels.
What words were they?Luke 9:26
26 For whosoever shall be ashamed of me and of my words, of him shall the Son of man be ashamed, when he shall come in his own glory, and in his Father’s, and of the holy angels.
Do Jesus's words that he sent them out to teach still apply?
How can one be ashamed of Jesus's words?
If one is ashamed of Jesus's words, will he teach Jesus's words?
If one is ashamed of Jesus's words, will he obey them?
Maybe there's a clue in this.
Matthew 28
19 ¶Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:
20 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.