Verse 1-4 — The Pharisees and Sadducees were opposed to each other in principles and in conduct; yet they joined against Christ. But they desired a sign of their own choosing: they despised those signs which relieved the necessity of the sick and sorrowful, and called for something else which would gratify the curiosity of the proud. It is great hypocrisy, when we slight the signs of God's ordaining, to seek for signs of our own devising.
Verse 5-12 — Christ speaks of spiritual things under a similitude, and the disciples misunderstand him of carnal things. He took it ill that they should think him as thoughtful about bread as they were; that they should be so little acquainted with his way of preaching. Then understood they what he meant. Christ teaches by the Spirit of wisdom in the heart, opening the understanding to the Spirit of revelation in the word.
Verse 13-20 — Peter, for himself and his brethren, said that they were assured of our Lord's being the promised Messiah, the Son of the living God. This showed that they believed Jesus to be more than man. Our Lord declared Peter to be blessed, as the teaching of God made him differ from his unbelieving countrymen. Christ added that he had named him Peter, in allusion to his stability or firmness in professing the truth. The word translated "rock," is not the same word as Peter, but is of a similar meaning. Nothing can be more wrong than to suppose that Christ meant the person of Peter was the rock. Without doubt Christ himself is the Rock, the tried foundation of the church; and woe to him that attempts to lay any other! Peter's confession is this rock as to doctrine. If Jesus be not the Christ, those that own him are not of the church, but deceivers and deceived. Our Lord next declared the authority with which Peter would be invested. He spoke in the name of his brethren, and this related to them as well as to him. They had no certain knowledge of the characters of men, and were liable to mistakes and sins in their own conduct; but they were kept from error in stating the way of acceptance and salvation, the rule of obedience, the believer's character and experience, and the final doom of unbelievers and hypocrites. In such matters their decision was right, and it was confirmed in heaven. But all pretensions of any man, either to absolve or retain men's sins, are blasphemous and absurd. None can forgive sins but God only. And this binding and loosing, in the common language of the Jews, signified to forbid and to allow, or to teach what is lawful or unlawful.
Verse 21-23 — Christ reveals his mind to his people gradually. From that time, when the apostles had made the full confession of Christ, that he was the Son of God, he began to show them of his sufferings. He spake this to set right the mistakes of his disciples about the outward pomp and power of his kingdom. Those that follow Christ, must not expect great or high things in this world. Peter would have Christ to dread suffering as much as he did; but we mistake, if we measure Christ's love and patience by our own. We do not read of any thing said or done by any of his disciples, at any time, that Christ resented so much as this. Whoever takes us from that which is good, and would make us fear to do too much for God, speaks Satan's language. Whatever appears to be a temptation to sin, must be resisted with abhorrence, and not be parleyed with. Those that decline suffering for Christ, savour more of the things of man than of the things of God.
Verse 24-28 — A true disciple of Christ is one that does follow him in duty, and shall follow him to glory. He is one that walks in the same way Christ walked in, is led by his Spirit, and treads in his steps, whithersoever he goes. "Let him deny himself." If self-denial be a hard lesson, it is no more than what our Master learned and practised, to redeem us, and to teach us. "Let him take up his cross." The cross is here put for every trouble that befalls us. We are apt to think we could bear another's cross better than our own; but that is best which is appointed us, and we ought to make the best of it. We must not by our rashness and folly pull crosses down upon our own heads, but must take them up when they are in our way. If any man will have the name and credit of a disciple, let him follow Christ in the work and duty of a disciple. If all worldly things are worthless when compared with the life of the body, how forcible the same argument with respect to the soul and its state of never-ending happiness or misery! Thousands lose their souls for the most trifling gain, or the most worthless indulgence, nay, often from mere sloth and negligence. Whatever is the object for which men forsake Christ, that is the price at which Satan buys their souls. Yet one soul is worth more than all the world. This is Christ's judgment upon the matter; he knew the price of souls, for he redeemed them; nor would he underrate the world, for he made it. The dying transgressor cannot purchase one hour's respite to seek mercy for his perishing soul. Let us then learn rightly to value our souls, and Christ as the only Saviour of them.