4:4 But when the fullness of time had come, God sent his Son, born of a woman, born under the law,
4:5 in order to redeem those who were under the law, so that we might receive adoption as children.
4:6 And because you are children, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!”
4:7 So you are no longer a slave but a child, and if a child then also an heir, through God.
When Paul tells the Galatians that they are no longer slaves he is referring to slaves of the law and sin, not physical slaves. He will eventually address slaves in the physical sense at a later time. Paul’s emphasis here in verses 4-7 is that God did not redeem us and make us His children so that we can go on sinning or revert back to our own ways. Rather, He places His spirit inside of us so that we can walk in the spirit and in righteousness.
Do not be drawn aside by people who live recklessly. Do not fall back into your old ways thinking God will forgive you. Do not try to serve God and purposefully walk in sin. All who do so are missing out on a truly magnificent calling for their lives and they are sacrificing power of God for something that only brings death and destruction. We must walk each day with a thirst to be with the Lord and to do His work.