What does Genesis 31:20 mean?

Jacob tricked Laban. Literally, he deceived the deceiver. Jacob somehow managed to pack up his family and all of his belongings and leave without Laban knowing that it was happening. The previous verse may hold a clue to how Jacob pulled it off: Laban had gone to shear his sheep—a flock he had moved three days' journey away from Jacob specifically as an attempt to keep Jacob's profits low (Genesis 30:31–36).

It's hard to feel too badly for Laban. He had famously deceived Jacob on his wedding night twenty years earlier (Genesis 29:20–28). More recently, he had repeatedly attempted to cheat the father of his own grandchildren in business (Genesis 31:4–13). Even his own daughters recognized that their father prized his money over his own family (Genesis 31:14–16).

Still, would Jacob not have been able to leave if he told Laban he was going? Depending on the exact nature of their relationship, Jacob might or might not have been able to freely go, at least not along with his wives and children. Legal or not, we will later learn both that Jacob feared Laban might take his wives and children by force, and such a fear will be justified by Laban's own statements.

So, once again, Jacob is running away (Genesis 27:41–45; 28:1–5), but this time only as quickly as a long, large caravan could travel.