Genesis 22:15

And the angel of the Lord called unto Abraham out of heaven the second time,

Cross-reference

Genesis 22:11 is the first angelic call; 22:15 continues as the second call.

Isaiah 45:23 Related theme

In Isaiah 45:23, God again swears by himself, echoing the solemn promise to Abraham.

Hebrews 6:13 directly references God swearing by himself to Abraham, as in this event.