Narrated Abu Sa'eed:
that about Allah's saying: Thus we have made you a Wasata nation (2:143) - the Prophet (ﷺ) said: "The meaning of Wasata is just." (ES)
English reference (ES): Vol. 5, Book 44, Hadith 2961 (ES)
Arabic reference (ES): Book 47, Hadith 3222 (ES)