Matthew Poole and continuators on Matthew 16:21

21 From that time forth began Jesus to shew unto his disciples, how that he must go unto Jerusalem, and suffer many things of the elders, and chief priests, and scribes, and be killed, and be raised again the third day.

Our Lord taught his Hearers by degrees, as they were able to hear, and to bear his Instruction. He therefore first instructeth them in the Truth of his Divine Nature, and bringeth them to a firm, and steady Assent to this Proposition, That he was the Christ, the Son of God; lest they should have this Faith of their's shaken by his Sufferings, and Death, he beginneth to instruct them, as to those things, that when they saw it come to pass, they might not be offended, but wait for his Resurrection from the Dead.

Marginal references: Chap. 20.17. Mark 9.31. & 10.33. Luke 18.31. & 24.7.