CCC 457 The Word became flesh for us in order to save us by reconciling us with God, who “loved us and sent his Son to be the expiation for our sins”: “the Father has sent his Son as the Savior of the world”, and “he was revealed to take away sins”:1
Sick, our nature demanded to be healed; fallen, to be raised up; dead, to rise again. We had lost the possession of the good; it was necessary for it to be given back to us. Closed in the darkness, it was necessary to bring us the light; captives, we awaited a Savior; prisoners, help; slaves, a liberator. Are these things minor or insignificant? Did they not move God to descend to human nature and visit it, since humanity was in so miserable and unhappy a state?2
CCC 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.”3 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.4
1 I Jn 4:10; 4:14; 3:5.
2 St. Gregory of Nyssa, Orat. catech 15: PG 45, 48B.
3 1 Jn 4: 12; cf. Rom 8:23; 2 Cor 1:21.
4 Acts 1:8; cf. 1 Cor 13.