וַיַּכּ֗וּ אֵ֤ת כָּל־הֶֽעָרִים֙ סְבִיב֣וֹת גְּרָ֔ר כִּי־הָיָ֥ה פַֽחַד־יְהוָ֖ה עֲלֵיהֶ֑ם וַיָּבֹ֙זּוּ֙ אֶת־כָּל־הֶ֣עָרִ֔ים כִּֽי־בִזָּ֥ה רַבָּ֖ה הָיְתָ֥ה בָהֶֽם׃
And they smote all the cities round about Gerar; for a terror from the LORD came upon them; and they spoiled all the cities; for there was much spoil in them.
Pirkei DeRabbi Eliezer
The prayer of Samuel destroyed the power of the children of Agag against Israel, as it is said, "And Samuel broke Agag before the Lord in Gilgal" (ibid.).