Second, he mentioned the supernatural blessing Laban had enjoyed since Jacob arrived. Laban realized that this new contract was going to cost him more, but he still was interested in Jacob since he was aware of Jacob's worth to him. Jacob would receive any lambs born in the future that were speckled, spotted, or black, and any kids that were spotted or speckled. All the others would go to Laban. To better understand this, we must remember that in the Near East such colors were rare.
Sheep are usually white and goats are usually black or dark brown.
The exceptions to this rule are not numerous. Jacob even offered to go through the flocks that very day and remove any speckled, spotted, or black sheep and any spotted and speckled goats. With these removed, the chances of these rare colored lambs and kids would be further dimished. Jacob, knowing Laban's suspicious nature, would have a means of defending what was rightly his and could not be falsely accused of stealing Laban's flocks. This was actually even more of a concession to Laban, for if in the second generation Jacob's black sheep should bear white lambs, these apparently would go back to Laban.