Deuteronomy 25:18
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. 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.
Amalek met Israel by the way when they came out of Egypt and journeyed under God's leading, falling upon them from behind and smiting the hindmost, even all that were feeble behind, when Israel was faint and weary, because he feared not God. The assault struck those bringing up the rear and lagging behind, especially the weak and straggling ones too feeble to keep up, taking advantage of their vulnerable condition. Amalek was not ignorant of God's character and sovereignty but defied His power, mocked the wonders wrought for Israel's deliverance by the hand of Moses before the Egyptians, and made derision and sport of them. He ridiculed the fears of surrounding nations and of Israel, and boasted that his wise men and magicians could do all those wonders, even claiming that had Israel been captive in his power as in Pharaoh's, God Himself could not have delivered them. He despised Israel, swore by his gods to utterly consume the Hebrews so that none should escape and to bring down Israel's God so He could not deliver them, and vowed to plague them until not one was left.
Israel had not injured or threatened Amalek, so the assault was wholly unprovoked, made to manifest hatred and defiance of God by seeking to destroy His people. In lifting his hand against the wearied and defenseless ranks Amalek lifted his hand against God and His throne. Amalek had long been high-handed sinners whose crimes cried for vengeance, yet mercy still called them to repentance, but falling upon the wearied ranks sealed their nation's doom. God marked those boastful words against Him and decreed that the remembrance of Amalek should be blotted out from under heaven. That destruction was to be executed after Israel received rest by the very people they had despised, that all nations might mark the end of that proud and powerful people.
This wrong is the reason Israel was later commanded to remember Amalek's deed and blot out his remembrance. Saul was therefore not to preserve anything from a people under God's curse or use their spoil for sacrifices, and his sparing what God had devoted to destruction disobeyed that command. The verse reveals God's tender care for Israel even when they had grieved Him by departing from His counsel, with the Lord seeing enemies taking advantage of their circumstances to injure and bring suffering upon the weary journeying under His leading. It shows His care is over the weakest of His children, that no act of cruelty or oppression toward them is unmarked by Heaven, that His hand extends as a shield over all who love and fear Him, and that those who smite that hand meet the sword of justice because Amalek's hand was against the throne of Jehovah.
The verse stands as a warning that the curse and denunciation pronounced upon Amalek will fall on those who profess to be God's children yet follow Amalek's practices by overcoming the faint and weary and failing to manifest the spirit of Christ toward their brethren. Still greater condemnation rests on those who had light, opportunities and privileges yet act so. The same principle condemns treating the weary and vulnerable with disregard and attacking fellow workers who are worn and weary in God's service. It likewise condemns exposing the weaknesses, mistakes and sins of God's afflicted people in ways that trouble and discourage them and leave them vulnerable to their enemies rather than helping them.