"To ask the prayers of our brethren in heaven is not only conformable to Holy Scripture, but is prompted by the instincts of our nature. The Catholic doctrine of the Communion of Saints robs death of its terrors,...If my brother leaves me to cross the seas I believe that he continues to pray for me. And when he crosses the narrow sea of death and lands on the shores of eternity, why should he not pray for me still? What does death destroy? The body. The soul still lives and moves and has its being. It thinks and wills and remembers and loves. The dross of sin and selfishness and hatred are burned by the salutary fires of contrition, and nothing remains but the pure gold of charity.
O far be from us the dreary thought that death cuts off our friends entirely from us! Far be from us the heartless creed which declares a perpetual divorce between us and the just in heaven! Do not imagine when you lose a father or mother, a tender sister or brother, who die in the peace of Christ, that they are forgetful of you. The love they bore you on earth is purified and intensified in heaven. Or if your innocent child, regenerated in the waters of baptism, is snatched from you by death, be assured that, though separated from you in body, that child is with you in spirit and is repaying you a thousand-fold for the natural life it received from you. Be convinced that the golden link of prayer binds you to that angelic infant, and that it is continually offering its fervent petitions at the throne of God for you, that you may both be reunited in heaven.
But I hear men cry out with Pharisaical assurance, "You dishonor God, sir, in praying to the saints. You make void the mediatorship of Jesus Christ. You put the Creature above the Creator." How utterly groundless is this objection! We do not dishonor God in praying to the saints. We should, indeed, dishonor Him if we consulted the saints independently of God. But such is not our practice. The Catholic Church teaches, on the contrary, that God alone is the Giver of all good gifts; that He is the Source of all blessings, the Fountain of all goodness. She teaches that whatever happiness or glory or influence the saints possess, all comes from God. As the moon borrows her light from the sun, so do the blessed borrow their light from Jesus, "the Sun of Justice," the one Mediator (of redemption) of God and men." Hence, when we address the 'saints, we beg them to pray for us through the merits of Jesus Christ, while we ask Jesus to help us through His own merits. ...
God forbid that our supplications to our Father in heaven should diminish in proportion as our prayers to the Saints increase; for, after all, we must remember that, while the Church declares it necessary for 'salvation to pray to God, she merely asserts that it is "good and useful to invoke the saints." (Council of Trent session XXV.) To ask the prayers of the saints, far from being useless, is most profitable. By invoking their intercession, instead of one we 'have many praying for us. To our own tepid petitions we unite the fervent supplications of the blessed and 'the Lord will hear the prayers of the just.'" Prov. XV, 29 DOUAY-RHEIMS. [Compare the RSV, and the NAB.] To the petitions of us, poor pilgrims in this [place] of tears, are united those of the citizens of heaven. We ask them to pray to their God and to our God, to their Father and to our Father, that we may one day share their delights in that blessed [place] in company with our common Redeemer, Jesus Christ, [the Lord]."
James Cardinal Gibbons, Archbishop of Baltimore, Faith of Our Fathers, pp. 131-33. (1876). ("Saints" here means not just the canonized saints but all those in heaven.)
Sec. "2683 The witnesses who have preceded us into the kingdom, [Cf. Heb 12:1] 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."(Cf. Mt 25:21 NASB, NAB) 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." Catechism of the Catholic Church.(Emphasis added.)
See Intercession of the Saints for statements by the Fathers of the Church on appealing to the saints for help. See also Rev. 5:8 and Rev. 8:3-4.
"When you are praying alone, and your spirit is dejected, and you are wearied and oppressed by your loneliness, remember then, as always, that God the Trinity looks upon you with eyes brighter than the sun; also all the angels, your own Guardian Angel, and all the Saints of God. Truly they do; for they are all one in God, and where God is, there are they also. Where the sun is, thither also are directed all its rays. Try to understand what this means."
St. John of Kronstadt
"[In honoring the saints, like St. Ignatius,] we may be able to become partakers with these saints, both of their dwelling and of their home, through the prayers of the saints themselves, through the grace and lovingkindness of our Lord Jesus Christ, with whom be glory to the Father with the Holy Spirit, now and always forever and ever amen." St. John Chrysostom
Look at the list of Patron Saints at the Catholic Online Saints and Angels page. See For all the Saints and especially the Excite Guide on Saints.
To view more on this part of Michelangelo's work see The Saved and the Lost. You can also see the Celestial World in the Last Judgement at Christus Rex's Cappella Sistina.
[The images used here are used with the permission of the copyright holder, Christus Rex. All material displayed here is for religious and educational purposes only. No other use is intended or permitted.]