Genesis 38:23 - Ellicott's Commentary On The Whole Bible

Lest we be shamed. — Maimonides asserts that Judah had committed no breach of the Law, the utmost therein commanded being that no Jewish woman should become a kedeshah (Deuteronomy 23:17). But Judah evidently regards what he had done as shameful, and having big friend’s testimony, if needed, to prove that he had performed what he promised, he bears with the loss of his signet and staff, rather than let the people know that he had been guilty of an act which they too would condemn.