John Gill Commentary Genesis 31:48

"And Laban said, This heap is witness between me and thee this day. Therefore was the name of it called Galeed:" — Genesis 31:48 (ASV)

And Laban said, this heap [is] a witness between me and thee this day. A witness of the covenant now about to be made between them that day, and a witness against them should they break it: therefore was the name of it called Galeed; by Jacob, as before observed; (See Gill on Genesis 31:47).