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