CCC 307 To human beings God even gives the power of freely sharing in his providence by entrusting them with the responsibility of “subduing” the earth and having dominion over it.1 God thus enables men to be intelligent and free causes in order to complete the work of creation, to perfect its harmony for their own good and that of their neighbors. Though often unconscious collaborators with God’s will, they can also enter deliberately into the divine plan by their actions, their prayers and their sufferings.2 They then fully become “God’s fellow workers” and co-workers for his kingdom.3

CCC 618 The cross is the unique sacrifice of Christ, the “one mediator between God and men”.4 But because in his incarnate divine person he has in some way united himself to every man, “the possibility of being made partners, in a way known to God, in the paschal mystery” is offered to all men.5 He calls his disciples to “take up [their] cross and follow [him]”,6 for “Christ also suffered for [us], leaving [us] an example so that [we] should follow in his steps.”7 In fact Jesus desires to associate with his redeeming sacrifice those who were to be its first beneficiaries.8 This is achieved supremely in the case of his mother, who was associated more intimately than any other person in the mystery of his redemptive suffering.9
Apart from the cross there is no other ladder by which we may get to heaven.10

CCC 772 It is in the Church that Christ fulfills and reveals his own mystery as the purpose of God’s plan: “to unite all things in him.”11 St. Paul calls the nuptial union of Christ and the Church “a great mystery.” Because she is united to Christ as to her bridegroom, she becomes a mystery in her turn.12 Contemplating this mystery in her, Paul exclaims: “Christ in you, the hope of glory.”13

CCC 1499 “By the sacred anointing of the sick and the prayer of the priests the whole Church commends those who are ill to the suffering and glorified Lord, that he may raise them up and save them. And indeed she exhorts them to contribute to the good of the People of God by freely uniting themselves to the Passion and death of Christ.”14

CCC 1508 The Holy Spirit gives to some a special charism of healing15 so as to make manifest the power of the grace of the risen Lord. But even the most intense prayers do not always obtain the healing of all illnesses. Thus St. Paul must learn from the Lord that “my grace is sufficient for you, for my power is made perfect in weakness,” and that the sufferings to be endured can mean that “in my flesh I complete what is lacking in Christ’s afflictions for the sake of his Body, that is, the Church.”16

1 Cf. Gen 1:26-28.
2 Cf. Col 1:24.
3 1 Cor 3:9; 1 Thes 3:2; Col 4:11.
4 1 Tim 2:5.
5 GS 22 # 5; cf. # 2.
6 Mt 16:24.
7 I Pt 2:21.
8 Cf Mk 10:39; Jn 21:18-19; Col 1:24.
9 Cf. Lk 2:35.
10 St. Rose of Lima: cf. P. Hansen, Vita mirabilis (Louvain, 1668).
11 Eph 1:10.
12 Eph 5:32; 3:9-11; 5:25-27.
13 Col 1:27.
14 LG 11; cf. Jas 5:14-16; Rom 8:17; Col 1:24; 2 Tim 2:11-12; 1 Pet 4:13.
15 Cf. 1 Cor 12:9, 28, 30.
16 2 Cor 12:9; Col 1:24.