When the Pharisees heard that Jesus had silenced the Sadducees, they gathered together, and one of them, a scholar of the law tested him by asking, "Teacher, which commandment in the law is the greatest?"
He said to him, "You shall love the Lord, your God, with all your heart, with all your soul, and with all your mind. This is the greatest and the first commandment.
The second is like it: You shall love your neighbor as yourself.
The whole law and the prophets depend on these two commandments."Matthew 22:34-40