Charles Ellicott Commentary Isaiah 63:12

"that caused his glorious arm to go at the right hand of Moses? that divided the waters before them, to make himself an everlasting name?" — Isaiah 63:12 (ASV)

With his glorious arm. —Literally, with the arm of His glory, or majesty. This, the arm of the Unseen Guide, is thought of as accompanying the leader of Israel, ready to grasp his hand and support him in time of need.

Dividing the water. —The words may include the passage of the Jordan, but refer primarily to that of the Red Sea (Psalms 106:9).