(20) باب النَّهْىِ أَنْ يَخْطُبَ الرَّجُلُ عَلَى خِطْبَةِ أَخِيهِ .
It was narrated from Abu Hurairah that the Messenger of Allah said:
"None of you should propose marriage to a woman when someone else has already proposed to her, unless he marries (and he gives up the idea), or gives him permission." (JA)
Reference (JA): Sunan an-Nasa'i 3241 (JA)
In-book reference (JA): Book 26, Hadith 46 (JA)
English translation (JA): Vol. 4, Book 26, Hadith 3243 (JA)