Malik related to me from al-Ala ibn Abd ar-Rahman from Mabad ibn
Kab as-Salami from his brother Abdullah ibn Kab ibn Malik al-Ansari
from Abu Umama that the Messenger of Allah, may Allah bless him and
grant him peace, said, "Whoever cuts off the right of a muslim man by
his oath, Allah forbids him the Garden and obliges the Fire for him."
They said, "Even if it is something insignificant, Messenger of
Allah?" He said, "Even if it is a tooth-stick, even if it is a tooth-
stick," repeating it three times.
Muwatta Malik Book 36, Hadith 15