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 , 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, 1Ti 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.
Apud Euseb. Praepar, Evangel. l. 9. c. 8. p.