From the Bible
Then one of them, which was a lawyer, asked Him a question, tempting Him, and saying,
Master, which ist the Great Commandment in the law?
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 ist 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.
St Matthew 22:35-40