Sunan an-Nasa'i, Volume 4, Book 26, Hadith 3244 (DarusSalam)

It was narrated from Abu Hurairah that the Prophet said: "None of you should propose marriage to a woman when someone else has already proposed to her."

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا غُنْدَرٌ، عَنْ هِشَامٍ، عَنْ مُحَمَّدٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ لاَ يَخْطُبْ أَحَدُكُمْ عَلَى خِطْبَةِ أَخِيهِ ‏" ‏ ‏.‏

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