What did Paul mean when he described the gospel as being "first to the Jew, then to the Greek" (Rom. 1:16)?

Some think the word “first” (Greek proton) should be taken sequentially, meaning the gospel was proclaimed first to the Jewish people and now it is for the “Greek” or the Gentiles. This is unlikely because the verb that governs the whole verse (“it is the power of God for salvation”) is a present tense. If the gospel is still the power of God for salvation and still for everyone who believes, it is still “first to the Jew.”

Others understand it to mean that the gospel should always be presented to Jewish people before reaching out to other people groups. The problem, once again, is that the word “first” does not require a sequential sense. In fact, most Greek dictionaries and lexicons say it does not have that kind of chronological meaning in this context.

It is best to understand the word “first” to mean “preeminently” or “especially.” This is how most Greek lexicons and dictionaries understand the word as used here. In fact, Paul uses the word “first” with this sense in Romans 2:9 and 3:2. The gospel is for all people, but it has special significance for the Jewish people. The promises of the Messiah and salvation were given to the Jewish people and, even if most rejected it, the gospel remains a message designed especially for them.