The Compendium of the Catechism of the Catholic Church (2006) teaches Roman Catholics to pray to both Mary and "the Saints." In fact, the Compendium states that Catholics should "ask them to intercede before the Holy Trinity for us and for the whole world." However, genuine believers should take care to note that the Bible simply does not teach us to pray to Mary or "the Saints." In fact, the Bible never even hints that God either desires or permits this practice. So, to whom should the Christian pray?
The best Biblical model that believers have for prayer is the Lord's prayer in Matthew chapter 4. There, Christ teaches that our prayers should be directed to God the Father in the name of the Son. I certainly don't think that this model prohibits directing prayer specifically to Christ. However, we may observe that, in His model prayer, Christ clearly taught us to pray to the Father:
Matthew 6:9 After this manner therefore pray ye: Our Father which art in heaven...
Other passages that teach the model of directing prayer to the Father (in the name of the Son) include John 15:16 and John 16:23:
John 15:16 "Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you."
John 16:23 "And in that day ye shall ask me nothing. Verily, verily, I say unto you, Whatsoever ye shall ask the Father in my name, he will give it you"
That said, it must be noted that we also have a clear New Testament example of prayer being directed specifically to Jesus, i.e. In Acts 7, when Stephen was stoned, he prayed to Jesus:
55 But he, being full of the Holy Ghost, looked up stedfastly into heaven, and saw the glory of God, and Jesus standing on the right hand of God, 56 And said, Behold, I see the heavens opened, and the Son of man standing on the right hand of God. 57 Then they cried out with a loud voice, and stopped their ears, and ran upon him with one accord, 58 And cast him out of the city, and stoned him: and the witnesses laid down their clothes at a young man’s feet, whose name was Saul. 59 And they stoned Stephen, calling upon God, and saying, Lord Jesus, receive my spirit. 60 And he kneeled down, and cried with a loud voice, Lord, lay not this sin to their charge. And when he had said this, he fell asleep.
In conclusion, the Bible never teaches Christians to pray to Mary or "the Saints." Rather, Jesus taught believers to pray to the Father in the name of the Son. We are also mindful of Stephen's example of praying to Christ.
Let us never forget that we have access to God the Father only because of Christ's perfect sacrifice upon the cross. "Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me" (John 14:6). It is only because of Christ that the believer may go "boldly unto the throne of grace" to "obtain mercy, and find grace to help in time of need" (Hebrews 4:16). Praise God!