Most of the laws were made in the Old Testament, and not even meant to be followed, but to prove that man cannot live a perfect life in God's eyes
This all changed with Jesus, who died on the cross and rose again
When he left Earth, he left them with The Holy Spirit, which is one of the Trinity
The Holy Spirit allowed followers to speak with confidence, and helped convert thousands
When someone has the Holy Spirit in them, it will guide them to make right decisions, with no need to study laws. If they are about to do something that is sinful, they will get a feeling that you're doing something wrong.
Hard to explain, but I've felt it before.
The main point of Christianity is having a loving relationship with Jesus