Hadith 26:43
Sahih (Darussalam)
Narrated Ibn 'Umar:
It was narrated from Ibn 'Umar 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 اللَّيْثُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " لاَ يَخْطُبْ أَحَدُكُمْ عَلَى خِطْبَةِ بَعْضٍ "
Original Reference: Sunan an-Nasa'i 3238