There was something that God thought was pertinent for man to know throughout the ages about the Athenians. It was not something that was flattering by any means, but a grave concern in the eyes of God—enough to inspire Luke to write about it. The Athenians wanted to hear Paul’s so-called “new doctrine,” because “all the Athenians and the foreigners who were there spent their time in nothing else but either to tell or to hear some new thing” (Acts 17:21).
There are people today (in and out of the church) who are reminiscent of the Athenians. They are fascinated by the idea of finding a “new” teaching in the Bible, which has never been discovered, or they find great satisfaction in discovering how the Bible really doesn’t teach some “old” truth but actually can be understood in some “new” way. God put Acts 17:21 in the Bible to warn us about seeking after or buying into “new” doctrines. When God’s people strayed from Him 2,600 years ago, He called them to “seek the old paths” (Jer. 6:16). That’s still sage advice for us today (cf. 2 Tim. 1:13)!