أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ لاَ يَخْطُبْ أَحَدُكُمْ عَلَى خِطْبَةِ بَعْضٍ ‏"‏ ‏.‏

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."