Catechism of the Catholic Church

733 "God is Love" ¹²⁴ and love is his first gift, containing all others. "God's love has been poured into our hearts through the Holy Spirit who has been given to us." ¹²⁵

734 Because we are dead or at least wounded through sin, the first effect of the gift of love is the forgiveness of our sins. The communion of the Holy Spirit ¹²⁶ in the Church restores to the baptized the divine likeness lost through sin.

735 He, then, gives us the "pledge" or "first fruits" of our inheritance: the very life of the Holy Trinity, which is to love as "God [has] loved us." ¹²⁷ This love (the "charity" of 1 Cor 13) is the source of the new life in Christ, made possible because we have received "power" from the Holy Spirit. ¹²⁸

736 By this power of the Spirit, God's children can bear much fruit. He who has grafted us onto the true vine will make us bear "the fruit of the Spirit: . . . love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control." ¹²⁹ "We live by the Spirit"; the more we renounce ourselves, the more we "walk by the Spirit." ¹³⁰

Through the Holy Spirit we are restored to paradise, led back to the Kingdom of heaven, and adopted as children, given confidence to call God "Father" and to share in Christ's grace, called children of light and given a share in eternal glory. ¹³¹