حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ مُحَمَّدِ بْنِ يَحْيَى بْنِ حَبَّانَ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ لاَ يَخْطُبُ أَحَدُكُمْ عَلَى خِطْبَةِ أَخِيهِ ‏"‏ ‏.‏

Yahya related to me from Malik from Muhammad ibn Yahya ibn Habbanfrom al-Araj from Abu Hurayra that the Messenger of Allah, may Allahbless him and grant him peace, said, "Do not ask for a woman inmarriage when another muslim has already done so." Translation Not Available

Book Ref: Muwatta Imam Malik Book 28 Hadith 1094
Web Ref:  Muwatta Imam Malik Book 28 Hadith 1