Leviticus 18:7

The nakedness of thy father, or the nakedness of thy mother, shalt thou not uncover: she is thy mother; thou shalt not uncover her nakedness.

Cross-references

Leviticus 18:6 provides the general incest prohibition that frames this specific rule about not uncovering your mother's nakedness.

Leviticus 20:11 prescribes the death penalty for this specific sin, adding the legal consequence.

Ezekiel 22:10 accuses Israel of committing this exact sin, showing its persistence.