Matthew 22:35-38

One of them, a lawyer [an expert in Mosaic Law], asked Jesus a question, to test Him: “Teacher, which is the greatest commandment in the Law?” [Mark 12:28] And Jesus replied to him, “ ‘YOU SHALL LOVE THE LORD YOUR GOD WITH ALL YOUR HEART, AND WITH ALL YOUR SOUL, AND WITH ALL YOUR MIND.’ [Deut 6:5] This is the first and greatest commandment.