1189 – Ibn ʿUmar (may Allah be pleased with them both) said: “The Prophet’s customary oath was: ‘No—by the Turner of hearts.’ ” Reported by al-Bukhārī (1).

1190 – ʿAbd Allāh ibn ʿAmr (may Allah be pleased with them both) said: “A Bedouin came to the Prophet ﷺ and asked, ‘Messenger of Allah, what are the major sins? …’ ” He then mentioned the rest of the narration, in which he said: “the plunging oath (al-yamīn al-ghamūs).” I asked, “What is the plunging oath?” He replied, “It is the oath by which a man seizes the property of a Muslim while knowingly lying.” Recorded by al-Bukhārī (2).

Vocabulary of the ḥadīth
• Major sins (kabāʾir): the gravest and most flagrant transgressions.
• Ghamūs: with an open ghayn; so called because it plunges (taghmus) the one who swears it into the Fire.

Points derived from the ḥadīth
1 – The plunging oath is an oath taken concerning a past matter while the swearer knows he is lying. It is called “plunging” because it immerses the person first in sin and then in Hellfire.

2 – The ḥadīth is evidence for the prohibition of the plunging oath and for its inclusion among the major sins. Its sin becomes even graver, and its danger more severe, when someone uses it to wrongfully appropriate the wealth of a fellow Muslim while lying.