“God’s Spirit doesn’t make us slaves who are afraid of him. Instead, we become his children and call him our Father. God’s Spirit makes us sure that we are his children.”Romans 8:15-16 CEV
There is a subtle difference between slave and child.
Both obey. Both submit. Both are under that authority.
The subtle difference is fear.
A slave responds out of fear for his or her life. When a slave sees he/she has to earn the master’s favor, or make up for the debt accrued, he/she will always be a slave to fear.
The only difference is the child responds to the love of God as His Father. A love that changed how the child sees his/her place in the family. A place that can’t be earned, only accepted. That’s why a child obeys.
The Holy Spirit is God’s gift to us to show us we are accepted in the family. We have nothing to fear.