The placement of this pericope is the first thing to attend to in preparation for preaching.
The text occurs in the midst of scenes in Matthew where the identity of Jesus as the Christ is revealed and considered. Preceding the lesson are several miracles: the healings of the Canaanite woman's daughter and others at the Sea of Galilee and the feeding of the four thousand. There follow demands by the Pharisees and Sadducees for a sign as to who Jesus is. Immediately before our lesson, we find Peter's declaration of Jesus as the Messiah. Directly following this text are the stories of the Transfiguration and another healing. Clearly, Matthew's intention here is to emphasize the person and divinity of Jesus of Nazareth and to relate him to the Jewish expectation of the Messiah.
But here the Jewish expectation is turned on its ear in two ways. First, a Messiah, yes; but one that will suffer and be killed. Nothing could be more contrary to the hope and expectation of Israel than for its long awaited leader to go directly to the place where he would be in the most danger and there be tortured and killed. For the careful listener, Jesus includes a strong word of hope: "...and on the third day be raised." But, this is so far beyond human comprehension that the listeners miss it, and Peter jumps in to stay Jesus' contrary plan. One minute Peter is praised and promised to be the "rock" upon which Jesus will build his church (16:17-18), then chastised in the next. Peter was on a roller coaster ride which seemed to be headed for disaster. He was a Jew and could not fathom a Messiah who would give up his life just at the moment when he should be seizing the leadership of Israel. Peter spoke for all the disciples. He still speaks for us, because we too have our minds "set not on divine things but on human things." (16:23)
With this first contradiction of Jewish expectations comes our first homiletical move in this text. There may be witnesses and indications all around us that Jesus is the Messiah. Yet do we not still set our minds readily on human things and miss the Easter promise of resurrection and life? It is so much easier to imagine a Jesus who was a great moral leader, a teacher, even a miracle worker, than to comprehend that he could draw all humankind to himself in one great self-giving embrace. If we are preaching this message to the unchurched, it will take a bold witness from a trustworthy spokesperson to break through the human thoughts in order to reveal the truth of this contrary idea. If we are preaching to the choir, and to a congregation that knows of this magnificent hope, we will likely need to remind them of the ways in which we are still functioning on an all too human level. It is our default setting, but this passage can reset our habits of mind and action.
This passage is a sure cure for preaching that tends to turn Jesus into a moral example. It often sounds like this: "If Jesus was willing to die on the cross for you, then shouldn't you be willing to serve him in return?" Here is a comprehensible Messiah, a tit-for-tat leader who sets an example and expects people to follow. The moral of the Jesus story is to ask, "What Would Jesus Do?" But, this story demands that we reset our habit of having our minds set on human ideas. Jesus is to die, not as an example of good behavior, but so he could rise again and reveal the incomprehensible power of God to change the world.
The second expectation overturned here is being a disciple of the Messiah should be a stroll through the halls of power and prestige. The human way of thinking is represented by our national leadership. To know the President personally, to visit one's Senator and be called by name, to be invited to important events in Washington: these are the expectations of the acolytes of the powerful. People pay huge sums to have that kind of access. Human expectations surrounding the Messiah would not have been much different. The Pharisees and Sadducees wanted a clear sign (16:1-4). If they had gotten one, they would have gladly fallen in line and prepared themselves to parade in the excess glory left in the Messiah's wake. No sign was given. He was not that kind of leader. And, he did not seek that kind of follower. His followers were "to deny themselves and take up their cross." (16:24)
Here, too, is our second homiletical approach. We have heard that we should take up our cross. To some degree, we followers of Jesus do this gladly. We especially do those things that are not too dear. We serve on boring church committees, bearing our cross without complaint. We give more than we think is financially prudent and hope it doesn't put a dent in our lifestyle. We help out those people who annoy us, thinking we are bearing a burden. The list of little crosses is endless. But, the passage pushes--and so the preacher must push--deeper. To take up the cross is to deny oneself, not to safeguard one's way of life by chastening it with little taxations. This leads only to "forfeiture" of life. Jesus demands more. The Messiah requires more.
The problem is we are pretty poor at cross bearing. The disciples wouldn't have thought themselves any better. They had seen crosses and knew how life-crushing they were. For them, the thought of carrying a cross was a life and death matter. In the end, many of them did die because they followed the Messiah. For us, to bear a cross is a metaphorical idea. No one really expects to die in the process. But, even to deny ourselves seems too much to ask. We aren't much good at that either. Here is both the challenge and the good news in this text: If we follow Jesus, we will be seriously called to bear certain crosses and lose hold of our lifestyle, if not our life. Yet, in all our weakness and human mindedness, it is Jesus' own death on the cross that enables us to do what we cannot.
God's power is revealed not in walks through the porticos of power, but through the dusty alleys of weakness and misery. That is where Jesus walked. That is where he leads us to walk. That is where he strengthens us to bear the burdens of discipleship. It is his burden we take upon our shoulders. It is his strength that bears the weight. We do nothing on our own, but he can do much through us. Without him, Peter was no rock, but a stumbling block. With him, Peter was the church. With him, we are not powerless to deny ourselves but able to bear all he may give us. Lloyd Ogilvie once put it this way: "We say, 'But, Lord, I cannot.' And God says, 'I'm glad to hear you say that. Through you, I can.'"