Kings I 15:2

2 Thus said the Lord of hosts, Now will I take vengeance for what Amalec did to Israel, when he met him in the way as he came up out of Egypt.

Kings I 15:2 In-Context

1 And Samuel said to Saul, The Lord sent me to anoint thee king over Israel: and now hear the voice of the Lord.
2 Thus said the Lord of hosts, Now will I take vengeance for what Amalec did to Israel, when he met him in the way as he came up out of Egypt.
3 And now go, and thou shalt smite Amalec and Hierim and all that belongs to him, and thou shalt not save anything of him alive, but thou shalt utterly destroy him: and thou shalt devote him and all his to , and thou shalt spare nothing belonging to him; and thou shalt slay both man and woman, and infant and suckling, and calf and sheep, and camel and ass.
4 And Saul summoned the people, and he numbered them in Galgala, four hundred thousand regular troops, and Juda thirty thousand regular troops.
5 And Saul came to the cities of Amalec, and laid wait in the valley.

The Brenton translation of the Septuagint is in the public domain.