Bukhari Vol. 6 : No. 72 (Hadith)

Narrated Abu Wail (Radi-Allahu 'anhu):

'Abdullah bin Masud said, "Allah's Apostle (Sallallahu 'Alaihi Wa Sallam)
said, 'Whoever takes an oath when asked to do so, in which he may deprive a
Muslim of his property unlawfully, will meet Allah Who will be angry with
him.' So Allah revealed in confirmation of this statement:--"Verily! Those
who Purchase a small gain at the cost of Allah's Covenant and oaths, they
shall have no portion in the Hereafter..." (3.77) Then entered Al-Ash'ath
bin Qais and said, "What is Abu 'Abdur-Rahman narrating to you?" We
replied, "So-and-so."


Al-Ash'ath said, "This Verse was revealed in my connection. I had a well in
the land of my cousin (and he denied my possessing it). On that the Prophet
(Sallallahu 'Alaihi Wa Sallam) said to me, 'Either you bring forward a
proof or he (i.e. your cousin) takes an oath (to confirm his claim)' I
said, 'I am sure he would take a (false) oath, O Allah's Apostle.' He said,
'If somebody takes an oath when asked to do so through which he may deprive
a Muslim of his property (unlawfully) and he is a liar in his oath, he will
meet Allah Who will be angry with him.' "