Commentary for Genesis 31:44

והיה לעד means and LET GOD BE FOR A WITNESS.

‘VEHAYAH’ FOR A WITNESS. This means, “And let the Holy One, blessed be He, serve as a witness.” These are the words of Rashi. But this is not the usual sense of the expression. Rather, Laban is saying, “And let the covenant be for a witness between us, for he who violates it should be cursed with all the curses of the covenant,”²⁴⁰Deuteronomy 29:20. similar in meaning to the verse, And they shall be upon thee for a sign and for a wonder.²⁴¹Ibid., 28:46. The meaning of the verse here may be: “Let us establish a covenant by a permanent thing which will serve as a witness between us.” For this reason, Jacob set up a stone as a pillar, and this is the meaning of that which he said, This stone-heap be witness, and this pillar be witness.²⁴²Verse 52 here. A similar meaning is found in the verse, And Joshua said unto all the people: Behold, this stone shall be a witness against us.²⁴³Joshua 24:27.

ועתה לכה, we already explained the meaning of this expression on 19,32.