Matthew 16:21

(Verse 21) Then Jesus began to show his disciples that he must go to Jerusalem, and suffer many things from the elders, chief priests, and scribes, and be killed, and on the third day be raised. And the meaning is: Proclaim me then, when I have suffered these things, because it is not profitable to publicly proclaim Christ and make known his majesty to the people, who after a little while will see him whipped and crucified, and suffer many things from the elders, chief priests, and scribes. And now Jesus suffers many things from those who crucify the Son of God again (Heb. VI): and when the elders are thought to be in the Church, and the high priests, following the simple letter, kill the Son of God, who is wholly felt in spirit.

"From that time forth began He to show unto them that He must suffer. From that time." What time? When He had fixed the doctrine in them; when He had brought in the beginning of the Gentiles. But not even so did they understand what He said. "For the saying," it is said, "was hid from them;" and they were as in a kind of perplexity, not knowing that He must rise again. Therefore He rather dwells on the difficulties, and enlarges His discourse, that He may open their mind, and they may understand what it can be that He speaks of. "But they understood not, but the saying was hid from them, and they feared to ask this;" not whether He should die, but how, and in what manner, and what this mystery could be. For they did not even know what was this same rising again, and supposed it much better not to die.

And observe that it is not said,' He began to say,' or 'to teach,' but to show; for as things are said to be shown to the sense, so the things which Christ spake are said to be shown by Him. Nor indeed do I think, that to those who saw Him suffering many things in the flesh, were those things which they saw so shown as this representation in words showed to the disciples the mystery of the passion and resurrection of Christ. At that time, indeed, He only began to show them, and afterwards when they were more able to receive it, He showed them more fully; for all that Jesus began to do, that He accomplished. He must needs go to Jerusalem, to be put to death indeed in the Jerusalem which is below, but to rise again and reign in the heavenly Jerusalem. But when Christ rose again, and others were risen with Him, they no longer sought the Jerusalem which is beneath, or the house of prayer in it, but that which is above. He suffers many things from the elders of the earthly Jerusalem, that He may be glorified by those heavenly elders who receive His mercies. He rose again from the dead on the third day, that He may deliver from the evil one, and purchase for such as are so delivered this gift, that they be baptized in spirit, soul, and body, in the name of the Father, and the Son, and the Holy Spirit, who are three days perpetually present to those that through them have been made children of light.