Our Gemara on Amud Beis discusses the halachic impurity of idolatrous material. Rabbi Akiva equates it to tumas niddah.

Chanukas Hatorah (32) uses this to explain Rachel’s evasion when Lavan searched for his stolen idols (Bereishis 31:35). Rachel, hiding them under her, claimed she couldn’t rise due to her period. Though not niddah, she wasn’t lying, as the idols’ impurity equated to tumas niddah.

Impurity in Jewish theology ties to death and spiritual voids, opposing God’s life-giving energy. Purification rituals use seven (Bamidbar 19:11), symbolizing creation’s cycle and physicality’s loss. Menstruation represents lost potential life (seven days of impurity, Vayikra 15:19); post-childbirth reflects (7 or 2 x 7 days,Vayikra 12:2-5) the absence of growing life.

Idolatry signifies lost connection to God. Per Daf 42, the Gra (Sefer Olam 30) notes that prophecy and idolatry stem from similar spiritual yearnings. Tumas niddah, a stillborn potential, parallels idolatry’s misdirected spiritual impulses.

Rachel’s message to Lavan, who saw niddah blood as impure (Ramban, ibid), was multifaceted. He obviously had spiritual sensitivities and traditions: his idols were toxic, misdirected yearnings disconnecting from God rather than fostering attachment.