ISB ~ Galatians 4 v6

sent the Spirit:As the Father sent the Son to redeem all nations from sin (4:4), he likewise sent the Spirit to renew them for a life of sanctity. The joint mission of the Son and Spirit is to bring blessing to the whole human family and unify them in the divine family of God (CCC 689).

into our hearts:The Spirit fills us with God’s presence and love (Rom 5:5; 2 Cor 1:22). His divine assistance enables us to live righteously as sons and daughters of the Father (Rom 8:4; 1 Jn 3:7; CCC 1265-66, 1695). Abba!: Aramaic for “Father!” It bespeaks a new level of intimacy with the Father that Jesus opened (Mk 14:36) for the children of God (Rom 8:15) (CCC 683, 2766).