Jesus said I have not come to destroy the law and the prophets, but to fulfill. He also said "he that curseth his father or mother, let him die the death" which is a reference to the law Moses gave to stone a rebellious child who would curse or smite their parents. The laws in the old Testament about right and wrong behavior are still valid, and God expects us to follow. The book of Hebrews explicitly says what was done away with, which was restrictions on food, the levitical priesthood, and the ritual washings when someone was considered unclean. If it wasn't explicitly said it is nul and void, then it still stands. God didnt suddenly decide it's okay to cross dress, to sleep with your family members, to be a sexual degenerate and pervert, etc.