Israel being thus far reformed that they had acknowledged the Lord to be God, and had consented to the execution of Baal's prophets, that they might not seduce them any more, though this was far short of a thorough reformation, yet it was so far accepted that God thereupon opened the bottles of heaven, and poured out blessings upon his land, that very evening (as it should seem) on which they did this good work, which should have confirmed them in their reformation; see Hag 2:18, Hag 2:19.
I. Elijah sent Ahab to eat and drink, for joy that God had now accepted his works, and that rain was coming; see Ecc 9:7. Ahab had continued fasting all day, either religiously, it being a day of prayer, or for want of leisure, it being a day of great expectation; but now let him eat and rink for, though others perceive no sign of it, Elijah, by faith, hears the sound of abundance of rain, Kg1 18:41. God reveals his secrets to his servants the prophets; and yet, without a revelation, we may foresee that when man's judgments run down like a river God's mercy will. Rain is the river of God, Psa 65:9.
II. He himself retired to pray (for though God had promised rain, he must ask it, Zac 10:1), and to give thanks for God's answer by fire, now hoping for an answer by water. What he said we are not told; but, 1. He withdrew to a strange place, to the top of Carmel, which was very high and very private. Hence we read of those that hide themselves in the top of Carmel, Amo 9:3. There he would be alone. Those who are called to appear and act in public for God must yet find time to be private with him and keep up their converse with him in solitude. There he set himself, as it were, upon his watch-tower, like the prophet, Hab 2:1. 2. He put himself into a strange posture. He cast himself down on his knees upon the earth, in token of humility, reverence, and importunity, and put his face between his knees (that is, bowed his head so low that it touched his knees), thus abasing himself in the sense of his own meanness now that God had thus honoured him.
III. He ordered his servant to bring him notice as soon as he discerned a cloud arising out of the sea, the Mediterranean Sea, which he had a large prospect of from the top of Carmel. The sailors at this day call it Cape Carmel. Six times his servant goes to the point of the hill and sees nothing, brings no good news to his master; yet Elijah continues praying, will not be diverted so far as to go and see with his own eyes, but still sends his servant to see if he can discover any hopeful cloud, while he keeps his mind close and intent in prayer, and abides by it, as one that has taken up his father Jacob's resolution, I will not let thee go except thou bless me. Note, Though the answer of our fervent and believing supplications may not come quickly, yet we must continue instant in prayer, and not faint nor desist; for at the end it shall speak and not lie.
IV. A little cloud at length appeared, no bigger than a man's hand, which presently overspread the heavens and watered the earth, Kg1 18:44, Kg1 18:45. Great blessings often arise from small beginnings, and showers of plenty from a cloud of a span long. Let us therefore never despise the day of small things, but hope and wait for great things from it. This was not as a morning cloud, which passes away (though Israel's goodness was so), but one that produced a plentiful rain (Psa 68:9), and an earnest of more.
V. Elijah hereupon hastened Ahab home, and attended him himself. Ahab rode in his chariot, at ease and in state, Kg1 18:45. Elijah ran on foot before him. If Ahab had paid the respect to Elijah that he deserved he would have taken him into his chariot, as the eunuch did Philip, that he might honour him before the elders of Israel, and confer with him further about the reformation of the kingdom. But his corruptions got the better of his convictions, and he was glad to get clear of him, as Felix of Paul, when he dismissed him, and adjourned his conference with him to a more convenient season. But, since Ahab invites him not to ride with him, he will run before him (Kg1 18:46) as one of his footmen, that he may not seem to be lifted up with the great honour God had put upon him or to abate in his civil respect to his prince, though he reproved him faithfully. God's ministers should make it appear that, how great soever they look when they deliver God's message, yet they are far from affecting worldly grandeur: let them leave that to the kings of the earth.

Put his face between his knees - He kneeled down, and then bowed his head to the earth, so that, while his face was between his knees, his forehead touched the ground.

And it came to pass at the seventh time that he said, behold there ariseth a little cloud out of the sea, like a man's hand,.... Either about the size or in the form of it; rain water comes out of the sea, and, being strained through the clouds and air, becomes fresh:

and he said, go up: the meaning seems to be, that he should first go down from the mount, and then go up to that part of it where Ahab was:

say unto Ahab, prepare thy chariot; bind or fasten the horses to it, as the phrase seems to signify:

and get thee down; from the mountain where he was, to go to Jezreel, which lay low in a valley:

that the rain stop thee not; on the road, that might be made impassable by it, signifying that such abundance should fall as would make it so.

ELIJAH, BY PRAYER, OBTAINS RAIN. (Kg1 18:41-46)

Ahab went up to eat and to drink--Ahab, kept in painful excitement by the agonizing scene, had eaten nothing all the day. He was recommended to refresh himself without a moment's delay; and, while the king was thus occupied, the prophet, far from taking rest, was absorbed in prayer for the fulfilment of the promise (Kg1 18:1).

put his face between his knees--a posture of earnest supplication still used.