Sahih al-Bukhari 2258
Shuf'a
The partner should inform his partner before selling
Narrated `Amr bin Ash-Sharid: While I was standing with Sa`d bin Abi Waqqas, Al-Miswar bin Makhrama came and put his hand on my shoulder. Meanwhile Abu Rafi`, the freed slave of the Prophet (ﷺ) came and asked Sa`d to buy from him the (two) dwellings which were in his house. Sa`d said, "By Allah I will not buy them." Al- Miswar said, "By Allah, you shall buy them." Sa`d replied, "By Allah, I will not pay more than four thousand (Dirhams) by installments." Abu Rafi` said, "I have been offered five hundred Dinars (for it) and had I not heard the Prophet (ﷺ) saying, 'The neighbor has more right than anyone else because of his nearness, I would not give them to you for four-thousand (Dirhams) while I am offered five-hundred Dinars (one Dinar equals ten Dirhams) for them." So, he sold it to Sa`d.