Genesis 31:50
If thou shalt afflict my daughters, or if thou shalt take other wives beside my daughters, no man is with us; see, God is witness betwixt me and thee. If thou shalt afflict my daughters, or if thou shalt take other wives beside my daughters, no man is with us; see, God is witness betwixt me and thee.
Jacob, growing weary of Laban's service, asked to take his wives and children and go to his own place and country, but Laban urged him to remain because the Lord had blessed Laban for Jacob's sake. What Laban had before Jacob came was little and had increased to a multitude, while Jacob increased exceedingly in cattle, maidservants, menservants, camels and asses. Laban became envious of Jacob's greater prosperity and his countenance was not toward Jacob as before, and Laban's sons shared the jealousy and accused Jacob of taking away all their father's goods to get this glory. Jacob would have left long before but for fear of meeting Esau, and now he feared danger from Laban's sons, who counted his wealth as their own and might seize it by violence, leaving him perplexed and distressed, so mindful of the Bethel promise he carried his case to God for direction, and in a dream God answered him to return to the land of his fathers and to his kindred with the promise to be with him.
The verse belongs to the covenant of peace that Laban proposed after he could not deny Jacob's exposure of his selfish and grasping dealing, which Jacob accepted. The covenant was marked by a heap of stones and a pillar named Mizpah, meaning watch-tower. The heap and pillar stood as witnesses to a mutual pledge not to pass them to harm each other, sworn by the Fear of Isaac and confirmed by a shared feast and friendly communing through the night. With Laban's departure at dawn the covenant closed all trace of connection between the children of Abraham and the dwellers in Mesopotamia.
In the verse Laban guards the future happiness of Leah and Rachel as they journey far away where their interests will be entirely separate from his own, charging Jacob not to afflict his daughters and not to take other wives beside them, lest he bring still greater unhappiness upon himself and upon Leah and Rachel. Laban understood that polygamy is wrong and brings jealousy and unhappiness to the family, for the jealousy of Leah and Rachel had led them to give their maids to Jacob, which confused the family relation and increased the unhappiness of his daughters, yet Jacob had taken two wives, two sisters, only through Laban's own trickery and deception. When no man is with them, God is witness between them, invoked to watch between them when absent from one another and to act as witness and judge to protect the daughters' welfare and hold Jacob accountable. Jacob therefore made a solemn covenant before God, before the Lord, not to take other wives besides Laban's daughters.