A phrase like, "this is my doctrine," spoken directly from the mouth of the Master should raise the interest of all gospel doctrine lovers. The phrase occurs five times in the scriptures, and four of them occur in 3 Nephi 11 (see also DC 10:67). The four doctrines mentioned are 1) that contentions should be put away, 2) that all men are commanded to repent, believe in Christ, and be baptized, 3) that faith, repentance, and baptism are followed by the Holy Ghost's baptism by fire, and 4) that whoso buildeth upon this buildeth upon my rock, and the gates of hell shall not prevail against them (v. 39).
Jeffrey R. Holland
"The Savior stressed such strong, recurring themes as the unity of the Godhead and the need for all disciples to be as little children, but clearly the foundational doctrine of baptism is at the heart of Christ's saving ministry, for he repeated the phrase 'my doctrine'—particularly as applied to baptism—at least eight times in his unequivocal counsel to the Nephites." (Christ And The New Covenant, p. 261)