וְיָצָ֧אתִי אַחֲרָ֛יו וְהִכִּתִ֖יו וְהִצַּ֣לְתִּי מִפִּ֑יו וַיָּ֣קָם עָלַ֔י וְהֶחֱזַ֙קְתִּי֙ בִּזְקָנ֔וֹ וְהִכִּתִ֖יו וַהֲמִיתִּֽיו׃
I went out after him, and smote him, and delivered it out of his mouth; and when he arose against me, I caught him by his beard, and smote him, and slew him.
Rashi
ויחזק בו AND HE LAID HOLD OF IT —The phrase signifies “grasping” (אחז). There are many examples of it in the Scriptures: (Genesis 19:16) “The men laid hold of (ויחזיקו בְּ..) his hand”; (Deuteronomy 25:11) “And she layeth hold of (והחזיקה בְּ..) his secret parts”; (I Samuel 17:35) “And I caught him by (והחזקתי בְּ..) his beard”. [Wherever the root חזק in the Hiphil is followed by the preposition ב it denotes “taking hold of a thing”].