Numbers 5:13

And a man lie with her carnally, and it be hid from the eyes of her husband, and be kept close, and she be defiled, and there be no witness against her, neither she be taken with the manner;

Cross-reference

Leviticus 18:20 prohibits sexual relations with a neighbor's wife, the very act concealed in Numbers 5:13.

Leviticus 20:10 prescribes death for proven adultery, while Numbers 5:13 deals with hidden adultery requiring a test.

Romans 7:3 Allusion

In Romans 7:3, Paul reiterates the legal definition of adultery under the law, echoing the marital unfaithfulness context of Numbers 5:13.