None amongst you should outbid another in a transaction, nor should he make proposals of marriage upon the proposal made by someone else.  

عَنِ النَّبِيِّ ﷺ قَالَ لاَ يَبِعْ بَعْضُكُمْ عَلَى بَيْعِ بَعْضٍ وَلاَ يَخْطُبْ بَعْضُكُمْ عَلَى خِطْبَةِ بَعْضٍ  

That the Messenger of Allah ﷺ said: "None of you is to sell over the sale of others, nor to propose over the proposal of others." [He said:] There are narration on this topic from Abu Hurairah and Samurah.  

عَنِ النَّبِيِّ ﷺ قَالَ لاَ يَبِيعُ بَعْضُكُمْ عَلَى بَيْعِ بَعْضٍ وَلاَ يَخْطُبُ بَعْضُكُمْ عَلَى خِطْبَةِ بَعْضٍ قَالَ وَفِي الْبَابِ عَنْ أَبِي هُرَيْرَةَ وَسَمُرَةَ  

None amongst you should outbid another in a transaction, nor should he make proposals of marriage upon the proposal made by someone else. (Using translation from Muslim 1412a)  

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ لَا يَبِيعُ بَعْضُكُمْ عَلَى بَيْعِ بَعْضٍ وَلَا يَخْطُبُ بَعْضُكُمْ عَلَى خِطْبَةِ بَعْضٍ  

[Machine] According to the Messenger of Allah ﷺ , he said, "None of you should sell based on the sale of another, nor should anyone propose marriage to someone who has already been proposed to."  

عَنْ رَسُولِ اللهِ ﷺ أَنَّهُ قَالَ لَا يَبِيعُ بَعْضُكُمْعَلَى بَيْعِ بَعْضٍ وَلَا يَخْطُبُ عَلَى خِطْبَةِ بَعْضٍ