John Gill Commentary Genesis 31:50

"If thou shalt afflict my daughters, and if thou shalt take wives besides my daughters, no man is with us; see, God is witness betwixt me and thee." — Genesis 31:50 (ASV)

If you shall afflict my daughters In body or mind, by giving them hard blows, or ill words, and by withholding from them the necessaries of life, food and raiment, and the like:

or if you shall take [other] wives besides my daughters ; which also would be an affliction and vexation to them, see (Leviticus 18:18) . Laban, though he had led Jacob into polygamy, and even obliged him to it, did not choose he should go further into it, for the sake of his daughters, to whom he professes now much kindness and affection, though he had shown but little to them before; as well as talks in a more religious strain than he had been used to do:

no man [is] with us ; the sense is not that there were none with them at the present time, for the men or brethren that Laban brought with him were present: or that there were none fit to be witnesses, because these were kinsmen, for they are appealed to by Jacob as judges between them, (Genesis 31:33) ; but this refers to time to come, and may be supplied thus, "when no man be with us"; when there is none to observe what is done by either of us, contrary to mutual agreement, and to report it to one or other:

then see , take notice, and observe,

God [is] witness between me and you ; who is omniscient and omnipresent, sees, observes all the actions of men, and deals with them accordingly; and so will be a witness for or against each of us, as we shall behave in observing, or not observing, the terms of our covenant.