To swear and to take Oath (binding) upon Allah
It is narrated from Jundub bin Abdullah (May Allah be pleased with him) that Allah’s Messenger (May the peace and blessing of Allah be upon him) said: A man said: ‘By Allah! Allah would not forgive such and such (person).’ Thereupon Allah the Exalted and Glorious said: ‘Who is he who swears about Me that I would not grant pardon to so-and-so? I have granted pardon to so-and-so and blotted out your (the swearer’s) deeds.'” (Muslim)
According to another Hadith from Abu Hurairah (May Allah be pleased with him) the man who said it, was a faithful worshipper. Abu Hurairah (May Allah be pleased with him) said: “His one statement destroyed his life in this world and the Hereafter.”
Important issues of the Chapter
1) Warning against taking an oath binding on Allah.
2) Hell-fire is closer to us than the laces of our shoes.
3) So is the Garden (Paradise).
4) In this Hadith it is described that a man sometimes utters a sentence unintentionally but the consequences of that are grave (i.e. severe punishment).
5) Sometimes a man gets forgiveness from all his evil deeds because of a most detested matter to him.