I think what Paul did here in chapter 21 is super interesting!
Remember back in chapter 15, he and Barnabas were part of the discussion with the elders in Jerusalem, not to have Gentiles go through circumcision? Yet, in in the very next chapter (16), he circumcised Timothy “because of the Jews“. Now in this chapter (21) he purifies himself along with the four others who had taken a vow, so that “you (Paul) yourself also live in observance of the law.“ (vs. 24)
(Remember 18:18, when he too cut his hair for a vow?)
Isn’t that interesting?
I like what one commentary said, “Paul showed that he did not object to Jewish converts following Old Testtament customs voluntarily, so long as these same customs were not required of Gentile believers.”
It also pointed out that Paul was demonstrating what he said in 1 Cor. 9:22, he was willing to become “all things to all people” for the sake of furthering the kingdom.”
Do you find this as interesting as I do?