Why Pray to Mary? Because Jesus has given us his Blessed Mother as our great spiritual mother (Rev.12:17), a heavenly advocate who intercedes for us.
Some Christians will ask, “Why pray to Mary when we can go directly to Jesus?” And yet they have no problem asking others here on earth to pray for them, instead of simply and solely praying to Jesus on their own. Indeed, St. Paul says that God grants blessings “in answer to many prayers” (2 Cor. 1:11). And if the prayer of a righteous man on earth avails much with God (Jas. 5:16–18), how much more would prayers from one who has finished the race and now reigns with Christ in heaven?
Scripture elsewhere speaks of the “the assembly of the firstborn who are enrolled in heaven” and “the spirits of just men made perfect” (Heb. 12:23, emphasis added). Given their heavenly perfection in Jesus, which would include perfection in charity and thus concern for their brothers and sisters in Christ on earth (see 1 Cor. 2:12-26), we should not be surprised that Scripture presents these holy men and women of heaven bringing our prayers to Jesus the Lamb (Rev. 5:8), and that from the early Church onward Christians have asked the intercession of the saints who have gone before them to heaven.
In this light, we see that the saints—as faithful disciples of Jesus—are his collaborators, not his competitors in interceding for us. Consequently, because Mary is the Mother of God and the disciple par excellence (see Luke 1:28, 38), we should not be surprised that she is our preeminent intercessor among the angels and saints.