A Muslim should not purchase (in opposition) to his brother.
Sahih Muslim Book 21, Hadith 13
← Previous Hadith A person should not enter into a transaction when his brother is already making a transaction and he should not make a proposal of marriage when his brother has already made a proposal except when he gives permission.

Sahih Muslim Book 21, Hadith 12 Next Hadith → This hadith has been narrated on the authority of Abu Huraira through another chain of transmitters but with a slight change of words.

Sahih Muslim Book 21, Hadith 14