This is what the Catechism of the Catholic Church says about saints:

2683 The witnesses who have preceded us into the kingdom,[41] especially those whom the Church recognizes as saints, share in the living tradition of prayer by the example of their lives, the transmission of their writings, and their prayer today. They contemplate God, praise him and constantly care for those whom they have left on earth. When they entered into the joy of their Master, they were "put in charge of many things."[42] Their intercession is their most exalted service to God's plan. We can and should ask them to intercede for us and for the whole world.

2684 In the communion of saints, many and varied spiritualities have been developed throughout the history of the churches. The personal charism of some witnesses to God's love for men has been handed on, like "the spirit" of Elijah to Elisha and John the Baptist, so that their followers may have a share in this spirit.[43] A distinct spirituality can also arise at the point of convergence of liturgical and theological currents, bearing witness to the integration of the faith into a particular human environment and its history. The different schools of Christian spirituality share in the living tradition of prayer and are essential guides for the faithful. In their rich diversity they are refractions of the one pure light of the Holy Spirit.

1717 The Beatitudes depict the countenance of Jesus Christ and portray his charity. They express the vocation of the faithful associated with the glory of his Passion and Resurrection; they shed light on the actions and attitudes characteristic of the Christian life; they are the paradoxical promises that sustain hope in the midst of tribulations; they proclaim the blessings and rewards already secured, however dimly, for Christ's disciples; they have begun in the lives of the Virgin Mary and all the saints.

2030 It is in the Church, in communion with all the baptized, that the Christian fulfills his vocation. From the Church he receives the Word of God containing the teachings of "the law of Christ."[72] From the Church he receives the grace of the sacraments that sustains him on the "way." From the Church he learns the example of holiness and recognizes its model and source in the all-holy Virgin Mary; he discerns it in the authentic witness of those who live it; he discovers it in the spiritual tradition and long history of the saints who have gone before him and whom the liturgy celebrates in the rhythms of the sanctoral cycle.

2156 The sacrament of Baptism is conferred "in the name of the Father and of the Son and of the Holy Spirit."[85] In Baptism, the Lord's name sanctifies man, and the Christian receives his name in the Church. This can be the name of a saint, that is, of a disciple who has lived a life of exemplary fidelity to the Lord. The patron saint provides a model of charity; we are assured of his intercession. The "baptismal name" can also express a Christian mystery or Christian virtue. "Parents, sponsors, and the pastor are to see that a name is not given which is foreign to Christian sentiment."[86]

946 After confessing "the holy catholic Church," the Apostles' Creed adds "the communion of saints." In a certain sense this article is a further explanation of the preceding: "What is the Church if not the assembly of all the saints?"[477] The communion of saints is the Church.

948 The term "communion of saints" therefore has two closely linked meanings: communion in holy things (sancta)" and "among holy persons (sancti)." Sancta sancti's! ("God's holy gifts for God's holy people") is proclaimed by the celebrant in most Eastern liturgies during the elevation of the holy Gifts before the distribution of communion. The faithful (sancta) are fed by Christ's holy body and blood (sancta) to grow in the communion of the Holy Spirit (koinonia) and to communicate it to the world.

954 The three states of the Church. "When the Lord comes in glory, and all his angels with him, death will be no more and all things will be subject to him. But at the present time some of his disciples are pilgrims on earth. Others have died and are being purified, while still others are in glory, contemplating 'in full light, God himself triune and one, exactly as he is"':[490]

All of us, however, in varying degrees and in different ways share in the same charity towards God and our neighbors, and we all sing the one hymn of glory to our God. All, indeed, who are of Christ and who have his Spirit form one Church and in Christ cleave together.[491] 955 "So it is that the union of the wayfarers with the brethren who sleep in the peace of Christ is in no way interrupted, but on the contrary, according to the constant faith of the Church, this union is reinforced by an exchange of spiritual goods."[492]

956 The intercession of the saints. "Being more closely united to Christ, those who dwell in heaven fix the whole Church more firmly in holiness.... [T]hey do not cease to intercede with the Father for us, as they proffer the merits which they acquired on earth through the one mediator between God and men, Christ Jesus.... So by their fraternal concern is our weakness greatly helped."[493]

828 By canonizing some of the faithful, i.e., by solemnly pro claiming that they practiced heroic virtue and lived in fidelity to God's grace, the Church recognizes the power of the Spirit of holiness within her and sustains the hope of believers by proposing the saints to them as models and intercessors.[303] "The saints have always been the source and origin of renewal in the most difficult moments in the Church's history."[304] Indeed, "holiness is the hidden source and infallible measure of her apostolic activity and missionary zeal."[305]

[41] Cf. Heb 12:1.
[42] Cf. Mt 25:21.
[43] Cf. 2 Kings 2:9, Lk 1:1, PC 2.
[72] Gal 6:2.
[85] Cf. CIC, can. 1246; CCEO, cann. 881 § 1, § 4; 880 § 3.
[86] Cf. CIC, cann.1249-1251; CCEO, can. 882.
[477] Nicetas, Expl. symb. 10:PL 52:871B.
[490] LG 49; cf. Mt 25:31; 1 Cor 15:26-27; Council of Florence (1439): DS 1305.
[491] LG 49; cf. Eph 4:16.
[492] LG 49.
[493] LG 49; cf. 1 Tim 2:5.
[303] Cf. LG 40; 48-51.
[304] John Paul II, CL 16, 3.
[305] CL 17, 3.