Hadith 112
قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : " لا يَبِيعُ أَحَدُكُمْ عَلَى بَيْعِ أَخِيهِ، وَلا يَخْطُبُ عَلَى خِطْبَةِ أَخِيهِ "
And the Messenger of Allah, peace and blessings be upon him, said: "None of you should make a deal over the deal of his brother, nor should he send a proposal over the proposal of his brother."