Matthew 22:37-38 KJV
37 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.
38 This is the first and great commandment.
Mark 12:31 KJV
31 And the second is like, namely this, Thou shalt love thy neighbour as thyself. There is none other commandment greater than these.