Genesis 31:51-53

Living Bible

^51-52 This heap,” Laban continued, “stands between us as a witness of our vows that I will not cross this line to attack you and you will not cross it to attack me. ⁵³ I call upon the God of Abraham and Nahor, and of their father, to destroy either one of us who does.”

So Jacob took oath before the mighty God of his father, Isaac, to respect the boundary line.