The Jewish people had tried to live according to the Law, given to them by God through Moses. However, as St Paul would frequently preach, the Law was replaced by faith in Jesus Christ. “We know that a person is justified not by the works of the Law but through faith in Jesus Christ” (Gal. 2:16). Following him and doing as he commanded would be fulfilment of the Law.
Many people followed Jesus, but - as he had pointed out in the parable of the sower (Luke 8:4-8) - many people who heard what he said lacked a firm foundation. His miracles may have excited and attracted them. His feeding of the 5,000 (John 6:5-15) satisfied their hunger and must have filled them with awe. Now, however, he was taking them from their worldly concerns to a different dimension altogether. He was talking of himself as the living bread. He was asking them to commit themselves to taking on the life of the Spirit, where he would feed them with food that lasted forever. Many people could not and still do not accept the doctrine of the Eucharist. The disciples, however, realised that they had nowhere else to go other than following Jesus. It would take them to the Cross and to their own personal suffering. However, he promised his followers that he would be with them until the end of time (Matt. 28:30). He continues to nourish them with himself in the Eucharist.