Note 2 at Gal. 4:2: The illustration Paul is making is a continuation of his thoughts in chapter 3. In Galatians 3:24-26, Paul likened the law to being our schoolmaster or PAIDAGOGOS (see note 10 at Gal. 3:24, p. 1070). There he was emphasizing the job of the law (Gal. 3:19, 21).

Now he is continuing that comparison but emphasizing the effect that relationship had on us. Under the law we were no better than slaves. We were constantly being told what to do and actually had no freedom to choose. Through Christ, we have been redeemed from the slave relationship to the law and are now sons with all the rights, privileges, and freedoms that go with that.