In Acts 27:9 we hear that Paul observed a Jewish feast. Does this mean all Christians should observe the feasts?
In Acts 27:9, we read:
Acts 27:9 When considerable time had passed and the voyage was now dangerous, since even the fast was already over, Paul began to admonish them
In this verse Luke was referring to the fast that accompanies Yom Kippur or the Day of Atonement, which occurs in early Autumn. His reason for mentioning the fast was to draw attention to the time of year, since sailing on the Mediterranean Sea in the Fall can be especially dangerous due to unpredictable weather.
Luke’s mention of the fast in this way does not necessarily mean Paul was observing the fast himself, since Luke uses the term merely as a point of reference on the Jewish calendar. Nevertheless, for argument's sake let's assume Paul did, indeed, observe the Jewish feasts from time to time, including observing the fast associated with Yom Kippur. Does Paul’s choice to observe the feasts become a rule for all Christians?
The answer is no. As we seek to interpret the Bible, we must make a distinction between what is “descriptive” verses what is “prescriptive." Many details in scripture are merely a description of events or people, but these descriptions are not intended by God to be a prescription for our choices and decisions.
For example, the Bible describes Abraham lying about his wife Sarah, and later taking his son to the top of a mountain to sacrifice him in obedience to God. These details are descriptive of Abraham’s life, but they are not prescriptive for the church today. Obviously, all Christians are not expected to follow Abraham’s example and lie about our wives – much less to sacrifice our children to God! Clearly, these scenes in the Bible are descriptions – not prescriptions!
Likewise, Paul may have chosen to observe the Jewish feasts at times or even to visit the temple to present alms (Acts 24:17-18), but these accounts of Paul’s life are given to us as descriptions, not prescriptions. Paul was acting in the liberty available to all Christians. As Christians, we have the liberty to celebrate the Jewish feasts if we desire and even to observe other aspects of Jewish culture and practice - so long as we don’t hold that our choices must become requirements for all Christians.
Paul chose to observe certain aspects of Jewish life for a variety of good reasons, including to silence his Jewish critics and out of an appreciation for how these feasts pointed to Christ. Paul's choices were described in scripture, but these descriptions of Paul’s choices do not trump the clear prescription given to Christians elsewhere in the Bible concerning Jewish law:
Rom. 7:6 But now we have been released from the Law, having died to that by which we were bound, so that we serve in newness of the Spirit and not in oldness of the letter.
Gal. 5:18 But if you are led by the Spirit, you are not under the Law.
As Christians, we are not bound to observe Jewish law, though we may voluntarily choose to observe certain aspects (like the feasts) if we wish. This is the Bible’s prescription to believers concerning these matters. So the Bible’s description of Paul’s choices does not become a prescription for all believers. We go elsewhere in the Bible to find the prescription.
For more teaching concerning a Christian's relationship to the Law of Moses, please read On Law and Liberty. Also, please consult the article "Do We Need the Old Testament Law?"