(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." (TR)
Reference (TR): Sunan an-Nasa'i 3241 (TR)
In-book reference (TR): Book 26, Hadith 46 (TR)
English translation (TR): Vol. 4, Book 26, Hadith 3243 (TR)