Exodus 17:16

for he said, Because the Lord hath sworn that the Lord will have war with Amalek from generation to generation. It was a vow with his hand upon the banner of Jehovah, the altar which he had built, that Israel should continue the war against the Amalekites until their total extinction had been accomplished. The present victory was an earnest of future victories over all the enemies. Thus all the enemies of the believers, of the Church of Christ, will eventually be conquered, but our prayers must arise to the Throne of Mercy without ceasing.