An oath is a means for selling a commodity and a means for destroying the profit

Highlighting the significance of taking oaths in Allah's name and that it should only be done when necessary.
Unlawful earnings, even if large in quantity, are deprived of blessing and void of goodness.
Al-Qāri said: The loss of blessing in the earned wealth may occur through either destruction that affects his wealth, spending it in ways that bring no benefit to him in this world or reward in the Hereafter, it remains with him but he is deprived of its benefit, or it is inherited by someone who does not appreciate it.
An-Nawawi said: It contains a prohibition against frequently swearing oaths in sale transactions, as swearing without necessity is disliked. Additionally, it promotes the merchandise, and the buyer may be deceived by the oath.
Frequent swearing is a deficiency in faith and a deficiency in monotheism because excessive swearing leads to two things: the first is carelessness and lack of concern in this regard, and the second is lying, for whoever frequently swears oaths is likely to fall into lying. Therefore, one should minimize this and refrain from swearing excessively, which is why Allah Almighty says: {But be mindful of your oaths.} [Surat al-Mā’idah: 89]