In Mark 12:30-31, Jesus says:
'One of the teachers of the law came and heard them debating. Noticing that Jesus had given them a good answer, he asked him, “Of all the commandments, which is the most important?”
“The most important one,” answered Jesus, “is this: ‘Hear, O Israel: The Lord our God, the Lord is one. Love the Lord your God with all your heart and with all your soul and with all your mind and with all your strength.’ The second is this: ‘Love your neighbour as yourself.’ There is no commandment greater than these.”'