Marriage (Kitab Al-Nikah)
12/18. Chapter:
Regarding it being disliked for a person to propose after his brother's proposal
Sunan Abi Dawud
حَدَّثَنَا أَحْمَدُ بْنُ عَمْرِو بْنِ السَّرْحِ، حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ يَخْطُبُ الرَّجُلُ عَلَى خِطْبَةِ أَخِيهِ " .
Abu Hurairah reported the Apostle of Allaah(ﷺ) as saying “ A man should not seek the hand of a woman in marriage when his brother has already sought her hand.”
Reference : Sunan Abi Dawud 2080In-book reference : Book 12, Hadith 35English translation : Book 11, Hadith 2075