Thou shalt not hate thy brother in thine heart: thou shalt in any wise reason with thy neighbour, and not suffer sin upon him. Thou shalt not avenge, nor bear any grudge against the children of thy people, but thou shalt love thy neighbour as thyself: I am the Lord.

The Bible (The Old Testament) (14th - 2nd C BC) Judeo-Christian sacred scripture [Tanakh, Hebrew Bible], incl. the Apocrypha (Deuterocanonicals)

Leviticus 19:17-18 (KJV)

See Matthew 22:36-40.