That the Messenger of Allah (ﷺ) said: "Whoever swears by a religion other than Islam while lying, then he is as he said."
Jami` at-Tirmidhi Book 20, Hadith 22
← Previous Hadith "We were seven brothers without a servant except one, and one of us slapped her, so the Prophet (ﷺ) ordered us to free her."

Jami` at-Tirmidhi Book 20, Hadith 21 Next Hadith → "I said: 'O Messenger of Allah! My sister vowed that she would walk to the House barefoot and without Khimar (covering).' The Prophet (ﷺ) said: 'Verily Allah will not do anything with the misery of your sister. She should ride, and cover, and fast three days.'"

Jami` at-Tirmidhi Book 20, Hadith 23