Here, Jesus explains what is meant when Mark calls him the Christ in Mark 1:1: he's going to suffer, die, and rise again.

Regarding the deutero-canonical books included in Catholic Bibles, 1 and 2 Maccabees for example were in the septuagint, used as a source for Bible translation. The works are mostly historical. Jesus contradicts the assertion made in those books that the Messiah will be a great military leader; for this reason, it's appropriate to exclude them from canon.

v31... who will reject Jesus? The Sanhedrin (elders, chief priests and scribes), made up of Pharisees and Sadducees. The most experienced men in Israel. Jesus was rejected by the best of his own people!

v32... Peter began to rebuke Jesus! He thinks Jesus is in error. Liberal theology falls into this trap, even rebuking actual scripture. Like Peter, these rebukers will one day be rebuked by Jesus himself.

v33... "Get behind me, Satan..." Peter is concerned with worldly kingdoms, not the Kingdom of God. Jesus is on his way to the cross regardless of Peter's misconceptions, and Peter can either come with him or get out of the way.

If you're going to follow Jesus, you have to do it with this level of resolve, and press on! For example, some make a habit of not coming to church regularly, and this is bad, as the author of Hebrews says. Do I follow my spouse who wants to stay home from church, or do I follow God? A believer must be resolved, and hold the line! Anything that gets in the way of following Jesus has to go.

Satan's opposition to the ministry of Jesus...

No one in the Gospel received a harsher rebuke than Peter, when Jesus called him Satan.

Matthew 4 tells us of Jesus's temptation by Satan in the wilderness... he was promising to give Jesus dominion of all the kingdoms of the world, without the cross. A path without suffering! Satan offers all of us a similar deal, an easy way out, which we too must reject.

Psalm 123... if we follow the Good Shepherd, he will protect us! It can be hard, but he promises to be with us.

We must be resolved to follow the Lord at all costs!