21 Were you called while a slave? Do not worry about it; but if you are able also to become free, rather do that. 22 For he who was called in the Lord while a slave, is the Lord’s freedman; likewise he who was called while free, is Christ’s slave. 23 You were bought with a price; do not become slaves of men. 24 Brethren, each one is to remain with God in that condition in which he was called.
What is Paul saying now and why? Slavery and circumcision? What is the connection? There isn't any. These are just examples. The point Paul is making is simple. Serve Christ as you are. Do not use your new found faith in Him as a reason make changes of any kind. Notice that with circumcision the instruction goes both ways. If you became a Christian as an uncircumcised man remain so. If you can as a circumcised man remain so. Why? Because Jesus is enough. He is more than enough. If you come to him as a slave and learn that slavery was never part of God's plan so not seek your freedom. God sees you. He knows your name. He knows where you sleep. He knows your task master. He also knows how to set you free. He set Joseph free from prison to rule the entire nation. He raised Daniel from a prisoner of war to 2nd in command next to the king of two successive empires. He used an Israelite slave girl in Syria to testify to the military commander of the one True God and brought faith to his entire household.
Again Paul's point is very simple. When we have Jesus we gave everything and more. Remain content both where you are (slave or free) and as you are (circumcised or uncircumcised). No change in position will make you more loved by God, more secure in His kingdom or more useful to Him in the here and now. He will direct your steps as needed. Trust Him and be content where you are. No change in your person needs to be made either. If you came to Christ with tattoos keep them. Jesus loves you as you are. Making external changes reinforces the false religious idea that we are loved and saved by God because of something we do or don't do or have or don't have.
Jesus saves. Jesus alone. Anything added or removed is an insult to Him and a twisting of the Story.