Adam Clarke on Genesis 31:35

The custom of women is upon me - This she knew must be a satisfactory reason to her father; for if the teraphim were used to any religious purpose, and they seem to have been used in this way, as Laban calls them his gods, he therefore could not suspect that a woman in such a situation, whose touch was considered as defiling, would have sat upon articles that were either the objects of his adoration, or used for any sacred purpose. The stratagem succeeded to her wish, and Laban departed without suspicion. It seems very natural to suppose that Rachel did believe that by the use of these teraphim Laban could find out their flight, and the direction they took, and therefore she stole them; and having stolen them she was afraid to acknowledge the theft, and probably might think that they might be of some use to herself. Therefore, for these reasons, she brought them away.