Albert Barnes Commentary Galatians 4:10

"Ye observe days, and months, and seasons, and years." — Galatians 4:10 (ASV)

You observe. The object of this verse is to specify some of the things to which they had become enslaved.

Days. The days referred to here are doubtless the days of the Jewish festivals. They had numerous days of such observances; and in addition to those specified in the Old Testament, the Jews had added many others, as days commemorative of the destruction and rebuilding of the temple, and other important events in their history.

It is not a fair interpretation of this to suppose that the apostle refers to the Sabbath, properly so called, for this was a part of the Decalogue and was observed by the Savior Himself and by the apostles also. It is a fair interpretation to apply it to all those days which are not commanded to be kept holy in the Scriptures; and therefore, the passage is as applicable to the observance of saints' days, and days in honor of particular events in sacred history, as to the days observed by the Galatians.

There is as real servitude in the observance of the numerous festivals and fasts in the Papal communion, and in some Protestant churches, as there was in the observance of the days in the Jewish ecclesiastical calendar. For anything I can see, such observances are as inconsistent now with the freedom of the gospel as they were in the time of Paul. We should observe as seasons of holy time only what can be proven that God has commanded us, and no more.

And months. This refers to the festivals of the new moon, kept by the Jews (Numbers 10:10; Numbers 28:11–14). On this festival, in addition to the daily sacrifice, two bullocks, a ram, and seven sheep a year old were offered in sacrifice. The appearance of the new moon was announced by the sound of trumpets. See Jahn, Archae., § 352.

And times. This refers to stated times—festivals returning periodically, such as the Passover, the Feast of Pentecost, and the Feast of Tabernacles. See Jahn, Archae., chapter 3, §§ 346–360.

And years. This refers to the sabbatical year or the year of jubilee. See Jahn, as cited above.