Genesis 29:23-25 New International Version (NIV)
23 But when evening came, he took his daughter Leah and brought her to Jacob, and Jacob made love to her. 24 And Laban gave his servant Zilpah to his daughter as her attendant.
25 When morning came, there was Leah! So Jacob said to Laban, “What is this you have done to me? I served you for Rachel, didn’t I? Why have you deceived me?”
Jacob became very angry when he learned that he had been tricked by Laban. Jacob had been a deceiver, but now he had been deceived. It is natural for us to become upset when there is an injustice done to us. Just remember what that feels like, so that you do not do an injustice to someone else. Sin has a way of coming back around. If you do happen to do an injustice to someone else, apologize and work to right the wrong. You will be glad you did.