Jesus Christ taught His followers to pray to "our Father in heaven" (Matthew 6:9 Matthew 6:9After this manner therefore pray you: Our Father which are in heaven, Hallowed be your name.
American King James Version×), and the example throughout Scripture is that prayer is communication with God and part of our worship of Him.
What else does the Bible say about where prayers should be directed? Paul wanted the Roman church's "prayers to God" (Romans 15:30 Romans 15:30Now I beseech you, brothers, for the Lord Jesus Christ's sake, and for the love of the Spirit, that you strive together with me in your prayers to God for me;
American King James Version×). Moses was to "pray to the Lord" (Numbers 21:7 Numbers 21:7Therefore the people came to Moses, and said, We have sinned, for we have spoken against the LORD, and against you; pray to the LORD, that he take away the serpents from us. And Moses prayed for the people.
American King James Version×), and David sang to God that "to You I will pray" (Psalms 5:2 Psalms 5:2Listen to the voice of my cry, my King, and my God: for to you will I pray.
American King James Version×). Christians can come directly to God's throne of grace (Hebrews 4:16 Hebrews 4:16Let us therefore come boldly to the throne of grace, that we may obtain mercy, and find grace to help in time of need.
American King James Version×), and the Bible clearly teaches that Jesus Christ intercedes for us (Hebrews 7:25 Hebrews 7:25Why he is able also to save them to the uttermost that come to God by him, seeing he ever lives to make intercession for them.
American King James Version×). We don't need saints to do that.
Scripture shows saints (true believers) refusing to accept the worship of people (Acts 10:26 Acts 10:26But Peter took him up, saying, Stand up; I myself also am a man.
American King James Version×; Acts 14:8-18 Acts 14:8-18  And there sat a certain man at Lystra, weak in his feet, being a cripple from his mother's womb, who never had walked:  The same heard Paul speak: who steadfastly beholding him, and perceiving that he had faith to be healed,  Said with a loud voice, Stand upright on your feet. And he leaped and walked.  And when the people saw what Paul had done, they lifted up their voices, saying in the speech of Lycaonia, The gods are come down to us in the likeness of men.  And they called Barnabas, Jupiter; and Paul, Mercurius, because he was the chief speaker.  Then the priest of Jupiter, which was before their city, brought oxen and garlands to the gates, and would have done sacrifice with the people.  Which when the apostles, Barnabas and Paul, heard of, they rent their clothes, and ran in among the people, crying out,  And saying, Sirs, why do you these things? We also are men of like passions with you, and preach to you that you should turn from these vanities to the living God, which made heaven, and earth, and the sea, and all things that are therein:  Who in times past suffered all nations to walk in their own ways.  Nevertheless he left not himself without witness, in that he did good, and gave us rain from heaven, and fruitful seasons, filling our hearts with food and gladness.  And with these sayings scarce restrained they the people, that they had not done sacrifice to them.
American King James Version×). The Bible also tells us not to worship angels (Colossians 2:18 Colossians 2:18 Let no man beguile you of your reward in a voluntary humility and worshipping of angels, intruding into those things which he has not seen, vainly puffed up by his fleshly mind,
American King James Version×), and it shows that angels refuse adoration and worship by humans (Revelation 19:10 Revelation 19:10And I fell at his feet to worship him. And he said to me, See you do it not: I am your fellow servant, and of your brothers that have the testimony of Jesus: worship God: for the testimony of Jesus is the spirit of prophecy.
American King James Version×).
Notice also Revelation 22:9 Revelation 22:9Then said he to me, See you do it not: for I am your fellow servant, and of your brothers the prophets, and of them which keep the sayings of this book: worship God.
American King James Version×, where the apostle John saw in vision the time after the resurrection and fell down in awe at the feet of the being talking to him. "Then he said to me, 'See that you do not do that. For I am your fellow servant, and of your brethren the prophets, and of those who keep the words of this book. Worship God.'"
Righteous created beings, whether human or angelic, refuse to be worshipped and they point us to worship the Creator. Only Satan and his followers seek others' adoration and worship (Matthew 4:9 Matthew 4:9And said to him, All these things will I give you, if you will fall down and worship me.
American King James Version×; Acts 8:9-11 Acts 8:9-11  But there was a certain man, called Simon, which beforetime in the same city used sorcery, and bewitched the people of Samaria, giving out that himself was some great one:  To whom they all gave heed, from the least to the greatest, saying, This man is the great power of God.  And to him they had regard, because that of long time he had bewitched them with sorceries.
American King James Version×; 2 Thessalonians 2:3-4 2 Thessalonians 2:3-4  Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;  Who opposes and exalts himself above all that is called God, or that is worshipped; so that he as God sits in the temple of God, showing himself that he is God.
American King James Version×).
In addition to all this, praying to dead saints today assumes the doctrine of the immortal soul, which many people are surprised to find is not taught in the Bible. The Bible teaches that death is like sleep that lasts until the resurrection at Jesus Christ's second coming (1 Thessalonians 4:13-16 1 Thessalonians 4:13-16  But I would not have you to be ignorant, brothers, concerning them which are asleep, that you sorrow not, even as others which have no hope.
 For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.
 For this we say to you by the word of the Lord, that we which are alive and remain to the coming of the Lord shall not prevent them which are asleep.
 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:
American King James Version×).
For more information, please read our booklet Who Is God?