Jesus directed some of his harshest criticism towards the pharisees and scribes. They were supposed to give leadership to the Jewish people, since they were experts in the Law. He in fact described them as occupying the seat of Moses (Matt. 23:2). The Law was given by God to bind the Israelites together in a nation faithful to him and, also to give a framework for harmonious living. However the scribes and pharisees used the Law to enhance their status, and they manipulated it so they could evade their responsibilities. The ritual washing was an outward show, which paid lip-service to God. Loving him and their neighbours did not seem important to them.
The fact that Jesus quoted Isaiah, who prophesied in the 8th century BC, meant that this abuse of the Law had gone on a long time. When he was brought before Pilate he told him that he came to “testify to the truth” (John 18:37). When Philip brought Nathanael to him he said: “Here truly is an Israelite in whom there is no deceit!” (John 1.47) Whatever the Pharisees and scribes thought, God is not deceived.
Where can I go from your spirit?
Or where can I flee from your presence?
(Psalm 139:7)