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