Why the Christians seem to be not following the laws of Mosses and the prophets as such?

Once you believe that Jesus is Messiah, you are to obey all the things he commanded you and the commandments of the apostles who were filled with the Holy sprit sent by Jesus. The new covenant made by Messiah is the fulfillment of the law and it is much more than the old covenant.

  1. The new covenant as promised has come and the old is obsolete. Jeremiah 31:31-34, Hebrews 8:1-13
  2. The new laws written in the hearts are that of love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control etc. Against such things there is no law. These include all the laws written so far and it does much more than the law. In Jesus Christ (Messiah) the fulfillment of law took place. These are the principles with which a real Christian lives. Please be aware that a lot of Christians you observe may be namesake Christians. Try Pentecostal Christians you will find some. In the new covenant circumcision is to the heart not on the body. Galatians 5:16-24
  3. An example of the old and new law in action is explained in the parable of the good Samaritan. The priest and the levite in this parable observed everything according to the old law but they lacked the cardinal purpose of it love, mercy etc. Luke 10:30-37
  4. Here Jesus was replacing the ceremonial laws of washing of the outside, eating of certain foods etc against cleansing the heart and mind. Matthew 15:1-20, Matthew 12:34, Luke 6:44-45, Matthew 13:35, Psalm 78:2
  5. God sanctified all food. 1. Acts 10:1-19, Acts 10:28, Acts 10:44-48 2. Acts 11:1-26
  6. All ceremonial laws are obsolete because the new law is written in the hearts. Hebrews 9:1-28
  7. The ceremonial laws of Mosses do not anymore bind Gentiles and Jews turning to God by the grace of Messiah. Purity of heart is required than word by word obedience of law. After your sincere effort your inability is atoned by the blood of Jesus. Acts 15:1-11
  8. Justification by following the law alone is impossible. Romans 3:10, Romans 3:23, Ecclesiastes 7:20, Jeremiah 17:9-10, Isaiah 64:6, 1 John 1:8, Romans 5:20
  9. The ceremonial laws of eating and drinking any more do not bind you. Colossians 2:8-21
  10. Here Jesus was relaxing the laws about Sabbath and writing them in the conscience of people. 1. Matthew 12:1-21, Mark 2:23-28, Mark 3:1-6, Luke 6:1-11 2. Luke 4:16-21, Luke 13:10-17, Luke 14:1-6, John 5:1-16, John 7:22-24, John 9:14
  11. The laws regarding Sabbath was so stringent before Messiah. Search the TaNaKh for Sabbath.
  12. Here Jesus the God himself is touching and going near the dead body and the people who touched the dead body thereby modifying the laws regarding outward cleanliness to the cleanliness of the heart. 1. Luke 7:11-15, Matthew 9:18-27, Mark 5:22-42 2. John 11:1-45 3. Luke 8:40-56
  13. Here a woman touches Jesus the God himself in her uncleanness and he does not object it. This modifies the laws regarding the uncleanness of woman and similar outward cleanliness. Matthew 9:19-22, Mark 5:25-34, Luke 8:43-48
  14. Forgiveness and loving the enemy are the ultimate laws written in the hearts by circumcision of the heart. Leviticus 19:18, Matthew 5:33-48, Exodus 21:24; Leviticus 24:20; Deuteronomy 19:21, Matthew 6:9-15, Matthew 18:21-35

The circumcision of the heart in the new covenant is outwardly expressed by the water baptism of the person. See water baptism.