Why do some scholars think St. Luke may have been a Gentile?

The belief that St. Luke was a Gentile is primarily based on a specific interpretation of the New Testament text Colossians 4:11. In this passage, the author draws a distinction between Luke and other colleagues who are described as being "of the circumcision." Many scholars have historically interpreted this phrase as a reference to Jewish Christians, leading to the conclusion that Luke, by exclusion, must have been a Gentile.1

However, this conclusion is debated by modern scholars. Many argue that the phrase "of the circumcision" likely refers specifically to Jewish Christians who strictly observed the rituals of Judaism, rather than to all Jewish Christians generally. Consequently, this distinction does not definitively prove that Luke was a non-Jew. Furthermore, Luke’s deep familiarity with the Old Testament and the thematic focus of his writings lead many experts to suggest that he was more likely a Jewish Christian who adopted a Greek lifestyle and was less rigorous regarding ritual observances.1