Parashas Acharei Mos · Passuk 18:19
Chabad.org — English translation + Rashi
Torah Temima points to Shabbos 13b.
English: A student who shared close physical proximity with his wife while she was a niddah died mid-life; the verse’s “do not approach” was applied without favoritism even to a Torah scholar.
Severity of approaching a niddah
The prohibition of approach is enforced with full severity; scholarly status does not exempt.