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." (PT)
English reference (PT): Vol. 5, Book 44, Hadith 2961 (PT)
Arabic reference (PT): Book 47, Hadith 3222 (PT)