This was basically the question posed to the first none Jewish Christians in the early church. The first Christians were of course Jews. But as the Gospel crossed territorial and cultural barriers the question arose, “Can I be saved without being circumcised and obeying all the laws of Moses?” To the religious Jew who had struggled all his life to keep the Law it was hard to conceive being right with God without strict obedience to Moses’ Law. The church debated and reasoned among themselves. Finally, the Apostles and Elders with the help of the Holy Spirit (Acts 15:28) came up with the answer and sent word by letter and word of mouth to the Gentiles who believed (Acts 15:23-29).
The answer in a nutshell from “the Message” Bible…
“Be careful not to get involved in activities connected with idols; avoid serving food offensive to Jewish Christians (blood, for instance); and guard the morality of sex and marriage. These guidelines are sufficient to keep relations congenial between us. And God be with you!” Acts 15:29, Message.
Keeping in mind that these were instructions to already saved Gentiles, understand that there are of course many other instructions given in the New Testament concerning Christian behavior. But this letter was written to specifically address the question of the necessity of circumcision and the Law of Moses. The answer basically came down to avoiding any behavior that would stumble their Jewish brothers and living a life of sexual purity before God.
There is much more to say about the importance of living sexually pure. But we’ll leave that up to your personal homework: Exodus 20:14; Matthew 5:27,28; 1Corinthians 6:9-11,18-7:6; Galatians 5:19-21; Colossians 3:5,6; 1Thessalonians 4:3.