CCC 244 The eternal origin of the Holy Spirit is revealed in his mission in time. The Spirit is sent to the apostles and to the Church both by the Father in the name of the Son, and by the Son in person, once he had returned to the Father.1 The sending of the person of the Spirit after Jesus’ glorification2 reveals in its fullness the mystery of the Holy Trinity.

CCC 526 To become a child in relation to God is the condition for entering the kingdom.3 For this, we must humble ourselves and become little. Even more: to become “children of God” we must be “born from above” or “born of God”.4 Only when Christ is formed in us will the mystery of Christmas be fulfilled in us.5 Christmas is the mystery of this “marvelous exchange”:
O marvelous exchange! Man’s Creator has become man, born of the Virgin. We have been made sharers in the divinity of Christ who humbled himself to share our humanity.6

CCC 675 Before Christ’s second coming the Church must pass through a final trial that will shake the faith of many believers.7 The persecution that accompanies her pilgrimage on earth8 will unveil the “mystery of iniquity” in the form of a religious deception offering men an apparent solution to their problems at the price of apostasy from the truth. The supreme religious deception is that of the Antichrist, a pseudo-messianism by which man glorifies himself in place of God and of his Messiah come in the flesh.9

CCC 690 Jesus is Christ, “anointed,” because the Spirit is his anointing, and everything that occurs from the Incarnation on derives from this fullness.10 When Christ is finally glorified,11 he can in turn send the Spirit from his place with the Father to those who believe in him: he communicates to them his glory,12 that is, the Holy Spirit who glorifies him.13 From that time on, this joint mission will be manifested in the children adopted by the Father in the Body of his Son: the mission of the Spirit of adoption is to unite them to Christ and make them live in him:
The notion of anointing suggests. .. that there is no distance between the Son and the Spirit. Indeed, just as between the surface of the body and the anointing with oil neither reason nor sensation recognizes any intermediary, so the contact of the Son with the Spirit is immediate, so that anyone who would make contact with the Son by faith must first encounter the oil by contact. In fact there is no part that is not covered by the Holy Spirit. That is why the confession of the Son’s Lordship is made in the Holy Spirit by those who receive him, the Spirit coming from all sides to those who approach the Son in faith.14

CCC 728 Jesus does not reveal the Holy Spirit fully, until he himself has been glorified through his Death and Resurrection. Nevertheless, little by little he alludes to him even in his teaching of the multitudes, as when he reveals that his own flesh will be food for the life of the world.15 He also alludes to the Spirit in speaking to Nicodemus,16 to the Samaritan woman,17 and to those who take part in the feast of Tabernacles.18 To his disciples he speaks openly of the Spirit in connection with prayer19 and with the witness they will have to bear.20

CCC 1999 The grace of Christ is the gratuitous gift that God makes to us of his own life, infused by the Holy Spirit into our soul to heal it of sin and to sanctify it. It is the sanctifying or deifying grace received in Baptism. It is in us the source of the work of sanctification:21
Therefore if any one is in Christ, he is a new creation; the old has passed away, behold, the new has come. All this is from God, who through Christ reconciled us to himself.22

CCC 2561 “You would have asked him, and he would have given you living water.”23 Paradoxically our prayer of petition is a response to the plea of the living God: “They have forsaken me, the fountain of living waters, and hewn out cisterns for themselves, broken cisterns that can hold no water!”24 Prayer is the response of faith to the free promise of salvation and also a response of love to the thirst of the only Son of God.25

1 Cf. Jn 14:26; 15:26; 16:14.
2 Cf. Jn 7:39.
3 Cf. Mt 18:3-4.
4 Jn 3 7; 1:13; 1:12; cf. Mt 23:12.
5 Cf. Gal 4:19.
6 LH, 1 January, Antiphon I of Evening Prayer.
7 Cf. Lk 18:8; Mt 24:12.
8 Cf. Lk 21:12; Jn 15:19-20.
9 Cf. 2 Th 2:4-12; I Th 5:2-3; 2 Jn 7; I Jn 2:1 8, 22.
10 Cf. Jn 3:34.
11 Jn 7:39.
12 Cf. Jn 17:22.
13 Cf. Jn 16:14.
14 St. Gregory of Nyssa, De Spiritu Sancto, 16: PG 45, 1321A-B.
15 Cf. Jn 6:27, 51, 62-63.
16 Cf. Jn 3:5-8.
17 Cf. Jn 4:10, 14, 23-24.
18 Cf. Jn 7:37-39.
19 Cf. Lk 11:13.
20 Cf. Mt 10:19-20.
21 Cf. Jn 4:14; 7:38-39.
22 2 Cor 5:17-18.
23 Jn 4:10.
24 Jer 2:13.
25 Cf. Jn 7:37-39; 19:28; Isa 12:3; 51:1; Zech 12:10; 13:1.