Amos 6:13

A thing of nought refers to the calf-worship, the idol that Israel is glorying and trusting in, the idolatrous travesty of the Eternal that they call “the excellency of Jacob.” (Comp. Amos 6:8, and Amos 8:7.)

Taken to us horns — i.e., instruments of resistance and aggression, the horn being symbolic of strength (Jeremiah 48:25; Psalms 75:10; Psalms 89:17; Psalms 92:10; 1 Samuel 2:10). The sacred historian takes quite a different view of the success of Jeroboam II. (2 Kings 14:26). These boasters reckoned the success of arms as due to their own ingenuity or “power.” (Comp. the language put into the mouth of Pharaoh by Ezekiel 29:3 : “My river is my own: I made it for myself.”)