Or HaChaim on Genesis 29:14/אור החיים על בראשית כ״ט:י״ד

1 ויאמר לו…אך עצמי ובשרי אתה, He said to him…"after all you are of my bone and flesh, etc." The word אך which is always a diminutive here serves to restrict the identification of Jacob with Laban.

2On the one hand Laban considered Jacob as his bone (self), on the other hand, he was well aware of the difference between them. Laban represented darkness rather than light. Perhaps he wanted to specify that all they had in common was flesh and bone.

3וישב עמו חודש ימים. He stayed with him for a month. He waited for a whole month, hoping that Jacob's possessions might arrive during that period. When he realised that there was no hope of that he had to decide how to relate to Jacob. Inasmuch as Laban had wanted Jacob to work for him from the moment he set eyes on him, he concealed this from him for a period of thirty days during which time Jacob worked without compensation. After that time he arranged working conditions with him for reasons which I shall explain later. During those thirty days he wanted to see if Jacob would prove to be an asset to him, if he would be successful. As a result of all this he had made a servant of Jacob from the very day he arrived; this is why he used the expression ועבדתני חנם, "you have already served me without compensation." Laban had satified himself during that month that Jacob was very successful in his work.