Note 1 at Mt 16:21: This was the fourth of fourteen times that Jesus prophesied about His death. (1st - Joh 2:19; 2nd - Mt 12:39-40; 3rd - Joh 6:51; 4th - this verse, Mr 8:31, and Lu 9:22; 5th - Mt 17:9-12; 6th - Mt 17:22-23, Mr 9:31, and Lu 9:44; 7th - Joh 10:17-18; 8th - Lu 11:29-30; 9th - Mt 20:17-19, Mr 10:32-34, and Lu 18:31-33; 10th - Mt 20:28; 11th - Joh 12:7-8; 12th - Joh 12:23-33; 13th - Mt 26:26-29, Mr 14:22-25, and Lu 22:19-20; and 14th - Mr 14:27-28.) Of these times, seven of His statements were made publicly (Mt 12:39-40; Lu 11:29-30; Joh 2:19, 6:51, 10:17-18, 12:7-8, and 23-33), while the remaining seven were made in private to His twelve disciples. Some of these prophecies were in parable form (Mt 12:39-40, 26:26-29 [and corresponding scriptures - the Lord's Supper]; Lu 11:29-30; Joh 2:19, and 12:23-32), but seven of these prophecies very clearly told of His resurrection on the third day.

Despite these abundant and clear prophecies about His death and resurrection, Jesus' disciples didn't understand or remember Jesus' words until after His resurrection (Lu 24:5-9). Luke twice recorded that Jesus' sayings about His resurrection were hidden from the disciples (Lu 9:45 and 18:34). It is interesting to note, however, that the chief priests and Pharisees remembered Jesus' prophecies about His resurrection (Mt 27:63) when His disciples didn't.

This incident happened approximately six months before Jesus' crucifixion. In the two and a half years of ministry prior to this, Jesus had only mentioned His death three times. But from this time forth, He began to expound on it more frequently, mentioning it eleven times in the next six months.