Answered by Shaykh Faraz Rabbani
Does swearing break wudu? if so, does this need to be said with the tongue or is thinking it enough?
Walaikum assalam wa rahmatullahi wa barakatuh,
I pray this finds you in the best of health and spirits.
No, swearing doesn’t affect one’s wudu in any way. However, swearing is impermissible and requires sincere repentence–one good expression of which is the prayer of repentance (salat al-tawba), which is two rakats of prayers performed after renewing one’s wudu and followed by seeking Allah’s forgiveness and repenting. (Ibn Abidin, Radd al-Muhtar)
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And Allah alone gives success.
Faraz Rabbani.