Sforno on Genesis 31:50/ספורנו על בראשית ל״א:נ׳

1ראה אלוקים עד, look that G’d will punish you if you do not treat my daughters properly, seeing He is a witness The whole line may be understood as analogous to Leviticus 5,21, ומעלה מעל בה', where the trespass against G’d is considered as something that only G’d is aware of, there being no human witnesses at hand to testify against the sinner. G’d is always the third party when two people have a disagreement, seeing He knows the true facts of the situation.