Love God with all your heart, and your neighbour as yourself.
On these two commandments hang all the law and the prophets.
What the Scriptures say
Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it, Thou shalt love thy neighbour as thyself. On these two commandments hang all the law and the prophets. Matthew 22:37-40 · KJV
And thou shalt love the LORD thy God with all thine heart, and with all thy soul, and with all thy might. Deuteronomy 6:5 · KJV
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. Leviticus 19:18 · KJV