Muhammad bin Amr says: I saw Sayyiduna Saib bin Khabbab (may Allah be pleased with him) smelling his garment. I asked: Why are you doing this? He said: I heard the Messenger of Allah (peace and blessings be upon him) say: Wudu is only required due to a bad smell or hearing the sound of wind.
Hadith Takhrij«حديث صحيح لغيره۔ أخرجه ابن ماجه: 516 ، (انظر مسند أحمد ترقيم الرسالة: 15506 ترقیم بيت الأفكار الدولية: 15591»
Brief Explanation
Benefits: … This ruling is for the person who, after performing ablution (wudu), begins to doubt whether his ablution has been nullified. That is, unless he becomes certain—by perceiving an odor or hearing a sound—that his ablution has indeed been nullified, his initial ablution remains valid. In the benefits of the next hadith, this very meaning is made clear from the aforementioned hadith.