1 Corinthians 9 : 19 For though I be free from all men, yet have I made myself servant unto all, that I might gain the more. 20 And unto the Jews I became as a Jew, that I might gain the Jews; to them that are under the law, as under the law, that I might gain them that are under the law; 21 To them that are without law, as without law, (being not without law to God, but under the law to Christ,) that I might gain them that are without law.

Again Paul is letting us know that the made himself free from all men by not receiving any support from them. This caused him to be enslaved to self support but it was so he could win more to Christ. He continues to let us know that even brought the message to the Jews because he was a Jew and he did this by following all the Jewish traditions, and even keeping the law even though they are no longer under the law. He did this to make sure he had a chance to get the Gospel to them. Paul, as we should, did what ever it took to get the message to the people he was witnessing to at the time.