All believers are but brethren. Hence, [whenever they are at odds,] make peace between your two brethren, and remain conscious of God, so that you might be graced with His mercy.
Al-Hujurat (The Dwellings) Verse 10
Some people asked Allah's Apostle, "Whose Islam is the best? i.e. (Who is a very good Muslim)?" He replied, "One who avoids harming the Muslims with his tongue and hands."
Volume 1, Book 2, Number 10