789/1 - Um Salamah (may Allah be pleased with her) reported: “The most beloved clothing to the Messenger of Allah (may Allah’s peace and blessings be upon him) was the Qamīs (long shirt).” [Narrated by Abu Dāwūd and Al-Tirmidhi who classified it as Hasan Sahīh (sound and authentic)]
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1) It is recommended to wear a Qamīs, for the Prophet (may Allah’s peace and blessings be upon him) used to wear it, and this was the most favorite clothing to him.
2) It is the Prophet’s guidance to wear what is more concealing of the ‘Awrah.