TT #250 · Parshas Shemini · Aliyah 7 · Passuk 43
Chabad.org — Vayikra Chapter 11 with Rashi
English: “Do not make yourselves detestable”: Rav Acha says that one who delays relieving himself violates the prohibition of making his soul detestable.
Makkot 16b.
E-Daf.com — Makkot 16b (Tsurras Hadaf)
Ethical application — The Chazal applies the verse’s wording and structure to establish the stated teaching.
Retaining bodily waste is included under the prohibition of bal teshaktsu.