Exodus 17:12 But Moses hands were heavy; and they took a stone, and put it under him, and he sat thereon; and Aaron and Hur stayed up his hands, the one on the one side, and the other on the other side; and his hands were steady until the going down of the sun. 13 And Joshua discomfited Amalek and his people with the edge of the sword.
[Patriarchs & Prophets pp 299>300] As the Hebrews triumphed when Moses was reaching his hands toward heaven and interceding in their behalf, so the Israel of God prevail when they by faith take hold upon the strength of their mighty Helper. Yet divine strength is to be combined with human effort. Moses did not believe that God would overcome their foes while Israel remained inactive. While the great leader was pleading with the Lord, Joshua and his brave followers were putting forth their utmost efforts to repulse the enemies of Israel and of God. After the defeat of the Amalekites, God directed Moses, “Write this for a memorial in a book, and rehearse it in the ears of Joshua: for I will utterly put out the remembrance of Amalek from under heaven.”
Just before his death the great leader delivered to his people the solemn charge: “Remember what Amalek did unto thee by the way, when ye were come forth out of Egypt; how he met thee by the way, and smote the hindmost of thee, even all that were feeble behind thee, when thou wast faint and weary; and he feared not God.... Thou shalt blot out the remembrance of Amalek from under heaven; thou shalt not forget it.” Deuteronomy 25:17-19. Concerning this wicked people the Lord declared, “The hand of Amalek is against the throne of Jehovah.” Exodus 17:16.
The Amalekites were not ignorant of God's character or of His sovereignty, but instead of fearing before Him, they had set themselves to defy His power. The wonders wrought by Moses before the Egyptians were made a subject of mockery by the people of Amalek, and the fears of surrounding nations were ridiculed. They had taken oath by their gods that they would destroy the Hebrews, so that not one should escape, and they boasted that Israel's God would be powerless to resist them. They had not been injured or threatened by the Israelites. Their assault was wholly unprovoked. It was to manifest their hatred and defiance of God that they sought to destroy His people.
Exodus 17:14 And the Lord said unto Moses, Write this for a memorial in a book, and rehearse it in the ears of Joshua: for I will utterly put out the remembrance of Amalek from under heaven.
May God add His blessing to the study of His word. "Good night" and God bless!