Matthew 22:35-40 The Pharisees, who had classified over 600 laws, often tried to distinguish the more important from the less important. So one of them, a lawyer, asked Jesus to identify the most important law. Jesus quoted from Deuteronomy 6:5 and Leviticus 19:18. By fulfilling these two commands, a person keeps all the other laws. They summarize the Ten Commandments and the other Old Testament moral laws.
Matthew 22:37-40 Jesus says that if we truly love God and our neighbor, we will naturally keep the commandments. This is looking at God's law positively. Rather than worrying about all we should NOT do, we should concentrate on all we CAN do to show our love for God and others.
Matthew 22:41-45 The Pharisees, Herodians and Sadducees had asked their questions. Then Jesus turned the tables and asked them a penetrating question - who they thought the Messiah was. The Pharisees knew that the Messiah would be a descendant of David, but they did not understand that He would be God Himself. Jesus quoted from Psalm 110:1 to show that the Messiah would be greater than David (Heb 1:13 uses the same text as proof of Christ's deity). The most important question we will ever answer is what we believe about Christ. Other theological questions are irrelevant until we believe that Jesus is who He said He is.
Matthew 23:2, 3 The Pharisees traditions and laws had become more important to them than God Himself. The problem arose when the religious leaders took man-made rules more seriously than God's laws. They told the people to obey these rules but did not do so themselves. Usually, Jesus did not condemn what the Pharisees taught, but what they were - hypocrites.