Fully conscious of this communion of the whole Mystical Body of Jesus Christ, the pilgrim Church from the very first ages of the Christian religion has cultivated with great piety the memory of the dead,(Cfr. Plurimae inseriptione in Catacumbis romanis.) and “because it is a holy and wholesome thought to pray for the dead that they may be loosed from their sins”,(2 Mach. 12, 46.) also offers suffrages for them. The Church has always believed that the apostles and Christ’s martyrs who had given the supreme witness of faith and charity by the shedding of their blood, are closely joined with us in Christ, and she has always venerated them with special devotion, together with the Blessed Virgin Mary and the holy angels.(Cfr. Gelasius I, Decretalis De libris recipiendis, 3: PL 59, 160, Denz. 165 (353).) The Church has piously implored the aid of their intercession. To these were soon added also those who had more closely imitated Christ’s virginity and poverty,(Cfr. S. Methodius, Symposion, VII, 3: GCS (Bodwetseh), p. 74) and finally others whom the outstanding practice of the Christian virtues (Cfr. Benedictus XV, Decretum approbationis virtutum in Causa beatificationis et canonizationis Servi Dei Ioannis Nepomuecni Neumann: AAS 14 (1922 p. 23; plures Allocutiones Pii X de Sanetis: Inviti all’croismo Diseorsi… t. I-III, Romae 1941-1942, passim; Pius XII, Discorsi Radiomessagi, t. 10, 1949, pp 37-43.) and the divine charisms recommended to the pious devotion and imitation of the faithful.(Cfr. Pius XII, Litt. Encycl : Mediator Dei: AAS 39 (1947) p . 581.)
Naturally, the particular make-up of the Communion of Saints is irrelevant when considering how they assist us with their prayers. However, the pantheon of saints also serves the Church on Earth as a body from which to draw models in the Christian life. As such, our late beloved pope, John Paul II did laity, particularly women, no favors by the relatively few numbers of saints he canonized who were neither clergy nor religious. Vatican II speaks of the importance of example in the “state in life and condition proper to each of us.”
When we look at the lives of those who have faithfully followed Christ, we are inspired with a new reason for seeking the City that is to come (Cf. Heb. 13, 14; 11, 10.) and at the same time we are shown a most safe path by which among the vicissitudes of this world, in keeping with the state in life and condition proper to each of us, we will be able to arrive at perfect union with Christ, that is, perfect holiness. (Cfr. Hebr. 13, 7: Eccli 44-50, Nebr. 11, 340. Cfr. etia Pius XII, Litt. Encycl. Mediati Dei: AAS 39 (1947) pp. 582-583) In the lives of those who, sharing in our humanity, are however more perfectly transformed into the image of Christ,(cf. 2 Cor. 3, 18.) God vividly manifests His presence and His face to (people). He speaks to us in them, and gives us a sign of His Kingdom,(Cfr. Cone. Vaticanum Const. De fide catholica, cap. 3 Denz. 1794 (3013).) to which we are strongly drawn, having so great a cloud of witnesses over us (Cf. Heb. 12, 1.) and such a witness to the truth of the Gospel.
Why Catholics appeal to the intercession of saints:
Nor is it by the title of example only that we cherish the memory of those in heaven, but still more in order that the union of the whole Church may be strengthened in the Spirit by the practice of fraternal charity.(Cf Eph 4, 1-6.) For just as Christian communion among wayfarers brings us closer to Christ, so our companionship with the saints joins us to Christ, from Whom as from its Fountain and Head issues every grace and the very life of the people of God.(Cfr. Pius XII, Litt. Encycl. Mystici Corporis: AAS 35 (1943) p. 216.) It is supremely fitting, therefore, that we love those friends and coheirs of Jesus Christ, who are also our brothers (and sisters) and extraordinary benefactors, that we render due thanks to God for them (Quoad gratitudinem erga ipsos Sanctos, cfr. E. Diehl, Inscriptiones latinae christianae vereres, 1, Berolini, 1925, nn. 2008 2382 et passim.) and “suppliantly invoke them and have recourse to their prayers, their power and help in obtaining benefits from God through His Son, Jesus Christ, who is our Redeemer and Saviour.”(Conc. Tridentinum, Sess. 25, De invocatione… Sanctorum: Denz. 984 (1821) .) For every genuine testimony of love shown by us to those in heaven, by its very nature tends toward and terminates in Christ who is the “crown of all saints,”(Breviarium Romanum, Invitatorium infesto Sanctorum Omnium.) and through Him, in God Who is wonderful in his saints and is magnified in them.(Cfr. v. g., 2 Thess. 1, 10.)
The role of the saints in the liturgy:
Our union with the Church in heaven is put into effect in its noblest manner especially in the sacred Liturgy, wherein the power of the Holy Spirit acts upon us through sacramental signs. Then, with combined rejoicing we celebrate together the praise of the divine majesty;(Conc. Vaticanum II, Const. De Sacra Liturgia, cap. 5, n. 104.) then all those from every tribe and tongue and people and nation (Cf. Apoc. 5, 9.) who have been redeemed by the blood of Christ and gathered together into one Church, with one song of praise magnify the one and triune God. Celebrating the Eucharistic sacrifice therefore, we are most closely united to the Church in heaven in communion with and venerating the memory first of all of the glorious ever-Virgin Mary, of Blessed Joseph and the blessed apostles and martyrs and of all the saints.(Canon Missae Romanae.)