Luke 9:18

Now the disciples were with the Lord, but He alone prayed to the Father, since the saints may be joined to the Lord in the bond of faith and love, but the Son alone is able to penetrate the incomprehensible secrets of the Father's will. Every where then He prays alone, for human wishes comprehend not the counsel of God, nor can any one be a partaker with Christ of the deep things of God. Rightly does our Lord, when about to enquire into the faith of the disciples, first inquire into the opinion of the multitudes, lest their confession should appear not to be determined by their knowledge, but to be formed by the opinion of the generality, and they should be considered not to believe from experience, but like Herod to be perplexed by different reports which they heard.

The way of advancing is explained in two ways. And it came to pass, when he was alone etc. After the Evangelist has set forth the form of preaching, in this part he sets forth the way of advancing. For advancement, these two considerations come …

When Christ was alone he was praying. It is good for us to improve our solitude for devotion, that, when we are alone, we may not be alone, but may have the Father with us. When Christ was alone, praying, his disciples were with him, to join with him in his prayer; so that this was a family-prayer.

And it came to pass, as he was alone praying,.... To his God and Father, for himself as man, and mediator; for the success of his Gospel, and the increase of his interest; and for his disciples, that they might have a clearer revelation of him; and which they had, as appears in their after confession of him by Peter, as the mouth of them all.

Let us notice in this passage — the variety of opinions about our Lord Jesus Christ, which prevailed during His earthly ministry. We are told that some said that He was John the Baptist — some that He was Elijah — and some that one of the old prophets had risen again. One common remark applies to all these opinions. All were agreed that our Lord's doctrine was not like that of the Scribes and Pharisees. All saw in Him, a bold witness against the evil that was in the world. Let it never surprise us, to find the same variety of opinions about Christ and His Gospel in our own times. God's truth disturbs the spiritual laziness of men. It obliges them to think. It makes them begin to talk, and reason, and speculate, and invent theories to account for its spread in some quarters, and its rejection in others. Thousands in every age of the Church spend their lives in this way, and never come to the point of drawing near to God. They satisfy themselves with a miserable round of gossip about this preacher's sermons — or that writer's opinions. They think "this man goes too far," and "that man does not go far enough." Some doctrines they approve, and others they disapprove. Some teachers they call "sound" — and others they call "unsound." They cannot quite make up their own minds what is true — or what is right. Year rolls on after year, and finds them in the same state — talking, criticizing, fault-finding, speculating — but never getting any further. They are hovering like the moth around religion — but never settling down like the bee , to feed on its treasures. They never boldly lay hold of Christ. They never set themselves heartily to the great business of serving God. They never take up the cross and become thorough Christians. And at last, after all their talking — they die in their sins, unprepared to meet God.

Let us notice in this passage — the variety of opinions about our Lord Jesus Christ, which prevailed during His earthly ministry. We are told that some said that He was John the Baptist — some that He was Elijah — and some that one of the old prophets had risen again. One common remark applies to all these opinions. All were agreed that our Lord's doctrine was not like that of the Scribes and Pharisees. All saw in Him, a bold witness against the evil that was in the world.

Whom say the people - Οἱ οχλοι, the common people, i.e. the mass of the people. See this question considered on Mat 16:13 (note), etc.

See the Mat 16:13-27 notes; Mar 8:27-38 notes. Luk 9:20 The Christ of God - The “Anointed” of God. The “Messiah” appointed by God, and who had been long promised by him. See the notes at Mat 1:1.