“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.”
Matthew 16:21 — Greek Interlinear
Church Fathers on Matthew 16:21
Seeing Peter had confessed Him to be Christ the Son of the living God, because He would not have them preach this in the mean time, He adds, 'Then charged he his disciples that they should tell no man, that he was Jesus the Christ.'
When then above He sends His disciples to preach, and commands them to proclaim His advent, this seems contrary to His command here, that they should not say that He is Jesus the Christ. To me it seems that it is one thing to preach Christ, and another to preach Jesus the Christ. Christ is a common title of dignity, Jesus the proper name of the Saviour.
For what having once had root has afterwards been torn up, if it is again planted, is with difficulty retained among the multitude; but what having been once rooted has continued ever after unmoved, is easily brought on to a further growth. He therefore dwells on these sorrowful things, and repeats His discourse upon them, that He may open the minds of His disciples.