Why Do Catholics Pray to Saints and Angels?
When the Jewish general Judas Maccabeus leads the resistance against the Greek occupation of their country, he tells his soldiers about "a dream, a kind of vision, worthy of belief" (2 Mc 15:11). In this vision, the general saw Onias, a former high priest who has died, praying with outstretched arms for the whole Jewish community" (15:12). Then he saw "God's prophet Jeremiah, who loves his brethren and fervently prays for his people and their holy city" (15:14): In part through the assistance of these two Old Testament saints, the Jewish fighters win their battle.
The angel Raphael tells the couple Tobit and Sarah: "When you... prayed, it was I who presented and read the record of your prayer before the Glory of the Lord" (Tb 12:12). Then the angel reveals that God sent him to heal them in answer to their prayer (see 12:14).
The New Testament displays similar scenes. Jesus' parable of Lazarus the beggar (see Lk 16:19-31) assumes that the deceased man is aware of those still living, is concerned with them, and wants to pray for them. In St. John's Revelation, the Christian martyrs in heaven know what is happening on earth, and they pray to God to accomplish justice there. In addition, both the saints and the angels in heaven bring to God's throne "the prayers of the holy ones" (see Rv 6:941; 5:6-8; 8:3-4).
In such passages, we find the saints and angels mediating before God for believers on earth, either interceding or otherwise assisting them. (In the parable, even someone in hell is attempting to do so, if unsuccessfully.) Does this contradict St. Paul's statement that "there is... one mediator between God and the human race, Christ Jesus" (1 Tm 2:5)? No, because the apostle wasn't excluding the participation of others in Christ's mediating role.
In fact, whenever Christians pray for one another, whether in heaven or on earth, they are doing just that. In a similar way, Jesus is the "chief" Shepherd of his flock (see Jn 10:11-16; 1 Pt 5:4), yet he assigns lesser shepherds to take part in this ministry (see Jn 21:15-17; Eph 4:11 ).
Catholics ask the saints and angels for their help, then, for the same reason they ask Christians on earth to pray for them and assist them in other ways: It has pleased God to make us interdependent as members of Christ's Body (see 1 Cor 12:12-27).