Rachel has stolen her father’s household idols (teraphim), thus removing the symbols of Laban’s authority. Laban’s pursuit of Jacob seems to be motivated primarily by the loss of the household gods. Jacob, innocent of the theft, pledges that the culprit will die and Laban searches the tents of all the women.
Rachel, however, has hidden the idols in a camel cushion and is sitting on them. She apologized for not standing when her father enters; her excuse is her menstrual period. So Laban does not find the gods and makes peace with the departing Jacob.
Rachel’s reasons for stealing the household idols are never stated. Is it her way of getting even with the father who so long ago denied her the wedding night? Is it her claim to Laban’s property? [Donna note: More recently, texts from Nuzi appear to indicate that these "gods" had more than religious significance–the holder of these items was to be recognized as the chief heir of family property. Perhaps Rachel, who (along with her sister Leah) felt that she had been defrauded by her father (vv. 14-16), was seeking by this rather drastic means to redress this wrong. One could also see why her father would be anxious to recover this stolen property.]
In any case, she proves herself as adept at deceiving her male relatives as her aunt Rebekah. Her claim of menstrual discomfort, whether true or not, subtly declares the uncleanness of the idols. Anything on which a menstruating woman sits is made unclean and anyone who touches anything on which she sits is also made unclean (Lev. 15:19-24). Idols are unclean by definition. Rachel’s action underlines that fact.
(Nowell, Irene., Women in the Old Testament, The Liturgical Press, Collegeville, Minnesota, 1991, pg 36)