An aspect of our worldly life that is often too easy for us to forget, is that the most powerful aspect of our Church is the Church Triumphant, and to remember it, carrying it with us as part of the spiritual armor sorely needed during our apostolate work on earth, is why daily practice is crucial—mass, prayer, rosary, recollection and examination—the spiritual swords of truth and the armor of God.
This article from Inside Catholic reminds us.
"The reasoning of the Church from remotest antiquity was simple: If I can ask you -- my brother or sister in Christ, who happen to be walking around on this earth -- to pray for me, then why can't I ask my brother or sister (or mother) in Christ to do the same?
Because the dead are dead? Not according to Jesus Christ:
“[H]ave you not read what was said to you by God, "I am the God of Abraham, and the God of Isaac, and the God of Jacob? He is not God of the dead, but of the living"? (Mt 22:31-32)
“Because they don't know what's happening on earth? The extremely dead Moses seemed to be pretty acutely aware of what was happening on earth when he appeared to Jesus and the apostles on the Mount of Transfiguration and "spoke of his departure, which he was to accomplish at Jerusalem" (Lk 9:31).
“Because they don't care? It runs rather counter to the logic of the entire tradition to say that the saints who have been perfected into the image and likeness of the God who is love will choose to express that love by being transformed into heavenly couch potatoes who do not give a rip about their suffering brothers and sisters on earth and who respond to the cries of the martyrs with, "I'm all right, Jack. I've got mine. Tough luck for you." Certainly the Letter to the Hebrews does not envision such a preposterous scenario, but instead sees us urged on with the love and prayers of the saints when it tells us: “Therefore, since we are surrounded by so great a cloud of witnesses, let us also lay aside every weight, and sin which clings so closely, and let us run with perseverance the race that is set before us, looking to Jesus the pioneer and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God. (Heb 12:1-2)
“And again when it concludes this passage by saying: “But you have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, and to innumerable angels in festal gathering, and to the assembly of the first-born who are enrolled in heaven, and to a judge who is God of all, and to the spirits of just men made perfect, and to Jesus, the mediator of a new covenant, and to the sprinkled blood that speaks more graciously than the blood of Abel.”
“The author of Hebrews, like the apostles at the Transfiguration, has a lively awareness that the saints in heaven are passionately involved with the progress of the Church on earth.”