The act represents the efficacy of intercessory prayer - offered doubtless by Moses - a point of great moment to the Israelites at that time and to the Church in all ages.

When Moses held up his hand - We cannot understand this transaction in any literal way; for the lifting up or letting down the hands of Moses could not, humanly speaking, influence the battle. It is likely that he held up the rod of God in his hand, Exodus 17:9, as an ensign to the people. We have already seen that in prayer the hands were generally lifted up and spread out, (See Clarke's note on Exodus 9:29), and therefore it is likely that by this act prayer and supplication are intended. The Jerusalem Targum says, "When Moses held up his hands in prayer, the house of Israel prevailed; and when he let down his hands from prayer, the house of Amalek prevailed." We may therefore conclude, that by holding up the hands in this case these two things were intended:

1. That hereby a reference was made to God, as the source whence all help and protection must come, and that on him alone they must depend.

2. That prayer and supplication to God are essentially necessary to their prevalence over all their enemies.

It is indisputably true that, while the hands are stretched out, that is, while the soul exerts itself in prayer and supplication to God, we are sure to conquer our spiritual adversaries; but if our hands become heavy - if we restrain prayer before God, Amalek will prevail - every spiritual foe, every internal corruption, will gain ground. Several of the fathers consider Moses, with his stretched-out hands, as a figure of Christ on the cross, suffering for mankind, and getting a complete victory over sin and Satan.

And it came to pass, when Moses held up his hand, that Israel prevailed,.... With his rod in it as a banner displayed, as some think, which inspired the Israelites with courage to fight, and they had the better of it; though Aben Ezra rejects that notion, observing, that if that had been the case, Aaron or Hur would have lifted it up, or fixed it in a high place on the mount, that it might have been seen standing; and therefore he thinks the sense of the ancients the most correct, that it was a prayer gesture. And among the Heathens, Moses was famous for the efficacy of his prayers; Numenius, the Pythagoric philosopher (y), says of him, that he was a man very powerful in prayer with God: and so all the Targums interpret it, and particularly the Targums of Jonathan and Jerusalem paraphrase the words,"when Moses lift up his hands in prayer, the house of Israel prevailed, but when he restrained his hands from prayer, the house of Amalek prevailed,''as it follows:

when he let down his hand, Amalek prevailed; so that victory seemed to go sometimes on one side, and sometimes on the other, according as the hand of Moses, with the rod in it, was held up or let down; when it was held up, and Israel saw it, they fought valiantly, but when it was let down, and they could not see it, their hearts failed them, and they feared it portended ill to them, which caused them to give way to the enemy. The spiritual Israel of God are engaged in a warfare with spiritual enemies, some within, and some without; and sometimes they prevail over their enemies, and sometimes their enemies prevail over them for a while; and things go on very much as a man either keeps up or leaves off praying, which is signified by the lifting up of holy hands without wrath and doubting, 1 Timothy 2:8 and which when rightly performed, under the influence of the divine Spirit in faith, in sincerity, and with fervency and constancy, has great power with God and Christ, and against Satan and every spiritual enemy.

(y) Apud Euseb. Praepar, Evangel. l. 9. c. 8. p. 411.

And it came to pass, when Moses held up his hand, that Israel prevailed: and when he let {g} down his hand, Amalek prevailed.

(g) So that we see how dangerous a thing it is to cease in prayer.

17:11 And when Moses held vp his hand in prayer (so the Chaldee explains it) Israel prevailed, but when he let down his hand from prayer, Amalek prevailed - To convince Israel that the hand of Moses (with whom they had just now been chiding) contributed more to their safety than their own hands; the success rises and falls, as Moses lifts up or lets down his hand. The church's cause is ordinarily more or less successful, according as the church's friends are more or less fervent in prayer.

17:8-16 Israel engaged with Amalek in their own necessary defence. God makes his people able, and calls them to various services for the good of his church. Joshua fights, Moses prays, both minister to Israel. The rod was held up, as the banner to encourage the soldiers. Also to God, by way of appeal to him. Moses was tired. The strongest arm will fail with being long held out; it is God only whose hand is stretched out still. We do not find that Joshua's hands were heavy in fighting, but Moses' hands were heavy in praying; the more spiritual any service is, the more apt we are to fail and flag in it. To convince Israel that the hand of Moses, whom they had been chiding, did more for their safety than their own hands, his rod than their sword, the success rises and falls as Moses lifts up or lets down his hands. The church's cause is more or less successful, as her friends are more or less strong in faith, and fervent in prayer. Moses, the man of God, is glad of help. We should not be shy, either of asking help from others, or of giving help to others. The hands of Moses being thus stayed, were steady till the going down of the sun. It was great encouragement to the people to see Joshua before them in the field of battle, and Moses above them on the hill. Christ is both to us; our Joshua, the Captain of our salvation, who fights our battles, and our Moses, who ever lives, making intercession above, that our faith fail not. Weapons formed against God's Israel cannot prosper long, and shall be broken at last. Moses must write what had been done, what Amalek had done against Israel; write their bitter hatred; write their cruel attempts; let them never be forgotten, nor what God had done for Israel in saving them from Amalek. Write what should be done; that in process of time Amalek should be totally ruined and rooted out. Amalek's destruction was typical of the destruction of all the enemies of Christ and his kingdom.