Slow to Understand
Jesus had been accused by the Pharisees of allowing His disciples to break God's Law. But they had not. They had broken the extra rules made up by the Pharisees, but those had no validity and did not have God's authority. The religious leaders believed that the more rules they could keep, the more pleased God would be with them - so they added extra clauses to God's law, until the ordinary people had no idea what had come from God.
The religious leaders claimed to know God's Word but ignored the parts which did not suit their way of thinking. In other words, they thought that they knew better than God. The Old Testament priests prepared food and ate it on the Sabbath and God was not cross with them; so why should He be angry when the disciples plucked a few ears of corn and rubbed the husks off in their hands before eating a little snack?
The Pharisees did not understand that God was for people, and not against them. Neither did they understand that religious observance was offensive to God if they failed to be merciful to the needy. So Jesus presents Himself as the Person who has the right to interpret God's Word - indeed ... because He is the Word of God (John 1:1-3).
Today, many people are expressing their views about what pleases God. However, we all need to come back to Jesus. Without His opinion we can have no wise understanding. Theologians, philosophers, mystics and the deluded can all express their thoughts; the internet is full of them. The important question is, "What did Jesus and his authorised Apostles say?" He has the right to determine what pleases God. Condemning the innocent is wicked, but unless we see God's heart through Jesus' eyes - we will make wrong judgements and condemn ourselves.