All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
A Muslim should not swear by Allaah The Almighty excessively because this contradicts the reverence that is due to Allaah and indicates that the person takes the matter of oaths lightly although Allaah The Almighty Says (what means):
· {But guard your oaths.} [Quran 5:89]
· {And do not obey every worthless habitual swearer.} [Quran 68:10]
Undoubtedly, if the swearer is a liar in his oath, then that will be more unlawful and his crime and sin will be more grievous and huge, especially if he seeks a worldly benefit thereby. It is narrated in an authentic Hadeeth that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said: “Allaah The Almighty Will neither Talk to, nor Look at three (types of) men (on the Day of Judgment) and they will have a painful torment.” We (the Companions) asked: “Who are those, O Messenger of Allaah? Let them fail and lose!” He, sallallaahu ‘alayhi wa sallam, said: “The one who reminds others of his favors on them, the one who lets his lower garment hang down (below his ankles), and the one who sells his goods by false oaths.” [At-Tirmithi who renders it Saheeh]
As to whether or not to believe a swearer, it is not binding. However, if the oath comes from a disobedient person, this makes it more appropriate not to believe him. If one is known for his negligence in prayers and other religious obligations, it is not strange that he deals recklessly with his oaths.
We ask Allaah for protection.
Allaah Knows best.