A common misinterpretation is that Paul endorses hypocrisy or compromise of core Christian beliefs, such as participating in sin or false religion to gain converts, ignoring the broader context where he clarifies he does not nullify God's law nor yield to legalism, but flexibly adapts non-essential cultural practices while remaining steadfast in faith, as seen in verses 21 and 22 emphasizing his ultimate allegiance to Christ.
I Corinthians 9:20
King James Version (1769)
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;
Paul articulates his evangelistic strategy of cultural adaptability, becoming like a Jew among Jews and like one under the law among those under the law, not to endorse legalism but to remove unnecessary barriers, making the gospel accessible and relatable so he might win more people to Christ without compromising his own freedom in the Spirit or the truth of salvation by grace.