Deuteronomy 18:10-14

Let me connect this to Galatians 4:10. God's own law forbids the observing of times. Is God contradictory? No, He is not. This is spoken to Israel. And God's holy days are not based on the observation of times. Certainly God's holy days are established each year by the movements of the heavenly bodies. But the observation of times goes beyond that. It involves the intercession of spirits and superstitious reading of omens in cloud formations, tealeaves, animal entrails, tarot cards, or the rolling of dice, and similar things. The modern day term is "augury."

Keeping His Sabbaths and reverencing His sanctuary in this context seems to imply very strongly what God had in mind when He inspired those comments forbidding the observing of times. To me, considering Paul's reverence for the Old Testament, he certainly did not have so-called "Jewish days" in mind at all. He had pagan practices in mind. Galatians 4:10 cannot be used to affirm that one is not to observe God's Sabbath and holy days.