4:3. So we also, when we were children, were serving under the elements of the world.
Under the elements, etc.... That is, under the first rudiments of religion, in which the carnal Jews were trained up; or under those corporeal creatures, used in their manifold rites, sacrifices, and sacraments.
4:4. But when the fulness of the time was come, God sent his Son, made of a woman, made under the law:
4:5. That he might redeem them who were under the law: that we might receive the adoption of sons.
4:6. And because you are sons, God hath sent the Spirit of his Son into your hearts, crying: Abba, Father.
4:7. Therefore, now he is not a servant, but a son. And if a son, an heir also through God.
4:8. But then indeed, not knowing God, you served them who, by nature, are not gods.
4:9. But now, after that you have known God, or rather are known by God: how turn you again to the weak and needy elements which you desire to serve again?
4:10. You observe days and months and times, and years.
You observe days, etc.... He speaks not of the observation of the Lord’s day, or other Christian festivals; but either of the superstitious observation of days lucky and unlucky; or else of the Jewish festivals, to the observance of which, certain Jewish teachers sought to induce the Galatians.