John Calvin Commentary Genesis 31:32

"With whomsoever thou findest thy gods, he shall not live: before our brethren discern thou what is thine with me, and take it to thee. For Jacob knew not that Rachel had stolen them." — Genesis 31:32 (ASV)

That Rachel had stolen them. Moses recounts how Rachel concealed her theft: specifically, by sitting on the idols and using the custom of women as a pretext.

It is a question whether she did this out of shame or obstinacy. It would have been disgraceful to be caught in the act of theft; she also dreaded the severe sentence of her husband.

Yet it seems probable to me that fear did not influence her as much as her obstinate love of idolatry. For we know how greatly superstition infatuates the mind.

Therefore, as if she had obtained an incomparable treasure, she thinks that she must attempt anything rather than allow herself to be deprived of it. Moreover, she chooses to incur the displeasure of her father and her husband rather than relinquish the object of her superstition. To her stratagem she also adds lying words, so that she deserves censure on many accounts.