The Jews, unlike their neighbours, worshipped the one God who through Moses gave them the Law, which they were to observe faithfully and which bound them together as a people. The scribes were legal experts who would do work like a modern solicitor, and the pharisees (some of whom could be scribes) were versed in the Law. The word "pharisee" means someone set apart.
It would be a mistake to think that all pharisees were bad. Nicodemus, who visited Jesus at night and who brought spices for his burial, was prepared to listen to him. Gamaliel was a highly respected teacher. St Paul, as a pharisee, was ideally suited to fulfil the role of apostle to the gentiles. Probably no-one else could have done what he did. The problem with the pharisees and scribes was that because they were educated, people looked up to them. Instead of realising that their gifts came from God, they paraded their virtue and basked in the adulation that they received.
Jesus saw that their elaborate washing rituals were merely giving lip-service to God; they behaved dishonestly and treated their people unkindly, castigating them as sinners. A good example of this occurred in the account in John’s gospel of the woman taken in adultery (John 8:1-11). The pharisees and teachers of the law put it to to Jesus that she be stoned. He, however, held a mirror to them when he said, “He who is without sin among you, let him be the first to cast a stone at her.”
Jesus came to call sinners, and for him compassion superseded the rigours of the Law.