Genesis 30:31-32

31Laban asked, ‘What must I give to you?’ Jacob replied, ‘You do not need to give me anything. But just do one thing for me. Then I will still take care of your animals. I will make sure that nothing bad happens to them.

32Do this: Let me go among all your animals today. Let me remove any animal that has a mark on it or that has more than one colour on its skin. I will also take any black lambs. That is what you will give me for my work.