Why do we pray to saints?
We really don’t pray to saints as much as we ask them to pray with and for us. In the same way we ask other people to pray for us, we ask saints for their intercession and their spiritual assistance. So just as I ask my friend to pray, I can also call upon St. Peter, St. Augustine, and St. Catherine and ask their intercession and their prayers. We believe that because the saints are already in heaven they are close to our Lord and can petition him on our behalf for the graces and needs that we have.
But why ask the saints for prayer? Why do we believe it is possible? One of the four marks of the Church (that we pray in the creed) is that the church is one, along with holy, catholic, and apostolic (CCC §811ff.). The Church—past, present, and future—is united in faith, purpose, and mission; we are one body, and in Christ all time and all people are united. This is the great communion of saints that highlights the unity of the body of Christ. As Jesus tells us in the synoptic Gospels, our God “is not God of the dead, but of the living, for to him all are alive” (cf. Lk 20:38; Mt 22:32; Mk 12:27). When we pray, we do so in union with the whole Church: saints and sinners, present and past, in solitude or community. We are one.