And when Moses lifted up his hands, Israel overcame: but if he let them down a little, Amalec overcame.

And it came to pass when Moses raised his hand, that Israel prevailed; and when he let down his hand, Amalek prevailed.

and it hath come to pass, when Moses lifteth up his hand, that Israel hath been mighty, and when he letteth his hands rest, that Amalek hath been mighty.

Now while Moses' hand was lifted up, Israel was the stronger: but when he let his hand go down, Amalek became the stronger.

And when Moses lifted up his hands, Israel prevailed. But when he released them a little while, Amalek overcame.

Et factum est, quum levaret Moses manum suam, praevaluit Israel, et quum demitteret manum suam, praevaluit Amalec.

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: 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.

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 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.