After feeding the multitude of people, Jesus and His disciples somehow manage to get that retreat they had planned. Jesus spends much of His time in prayer, but He also takes the opportunity to reveal some of God’s mysteries to the disciples. At this point, they probably don’t understand fully, and it’s not until later that they remember His words.
Jesus contrasts popular opinion of Himself with who the disciples think that He is. Peter, acting as the spokesman for the disciples as usual, gives the right answer: “The Christ of God”. (v. 20) “Christ” is Greek for “anointed”, and is the same as the Hebrew “Messiah”. It hearkens back to the priests and kings of Israel being anointed with oil to signify God choosing those men to fulfill those roles; they had been set apart from the rest of the people for a purpose.
Because the people didn’t understand what the Messiah’s role was going to be this first time, Jesus keeps His disciples from revealing this new understanding to anyone else. He then explains that He is going to suffer and die at the hands of evil men, but after three days would rise again. This sounds very obvious to us in the Church Age, but at the time the disciples didn’t get it, mostly because God kept them from understanding until the right time.
Even still, Jesus continues to teach them the consequences of following in His footsteps. They too must be willing to suffer and die, but the rewards they get from God will more than make up for it. The disciples must have been completely shocked to hear Jesus talk like this. It’d be like someone saying today, “Tie a noose around your neck and follow me,” or “Put a bullet with your name on it in your pocket and follow me.” None of those sound like good ideas! But the point Jesus is making is that it is worth it. Don’t be ashamed of the truth when people scoff and mock, or torture and kill you. For then God will not be ashamed of you when He comes in glory to set right everything on the earth again.
Finally, I’m going to punt on explaining verse 27. There are lots of possible ways to interpret it, and they all sound reasonable. The meaning of “see the Kingdom of God” is less important than the encouragement that the disciples received from hearing Jesus say so.
Help us to live for Your kingdom and not our own lives and pleasures. They are not a lasting legacy when compared to Your glory.