Bible Questions? Romans

What is the difference between the spirit of bondage and the Spirit of adoption (Romans 8:15-16)?

Romans 8:15-16 “For you did not receive the spirit of slavery to fall back into fear, but you have received the Spirit of adoption as sons, by whom we cry, “Abba! Father!” The Spirit himself bears witness with our spirit that we are children of God,” To understand the meaning of the “spirit of bondage/slavery” and …