Then one of the scribes came, and having heard them reasoning together, perceiving that He had answered them well, asked Him, "Which is the first commandment of all?"
References for Mark 12:28
Jesus answered him, "The first of all the commandments is: 'Hear, O Israel, the Lord our God, the Lord is one.
And you shall love the Lord your God with all your heart, with all your soul, with all your mind, and with all your strength.' This is the first commandment.
References for Mark 12:30
And the second, like it, is this: 'You shall love your neighbor as yourself.' There is no other commandment greater than these."
References for Mark 12:31
So the scribe said to Him, "Well said, Teacher. You have spoken the truth, for there is one God, and there is no other but He.
And to love Him with all the heart, with all the understanding, with all the soul, and with all the strength, and to love one's neighbor as oneself, is more than all the whole burnt offerings and sacrifices."
References for Mark 12:33