Definition of the word Pray
Merriam Webster: Etymology: Middle English, from Old French preier, from Latin precari, from prec-, prex request, prayer; akin to Old High German frAgEn to ask, Sanskrit prcchati he asks Date: 13th century transitive senses
1 : ENTREAT, IMPLORE -- often used as a function word in introducing a question, request, or plea <pray be careful>
2 : to get or bring by praying  intransitive senses  1 : to make a request in a humble manner  2 : to address God or a god with adoration, confession, supplication, or thanksgiving
PRAYING TO SAINTS IN HEAVEN
Mary's concieved without sin
"The Mighty One has done great things for me, and holy is his name."
Luke 1:49

Honoring Mother Mary The Mother of God
"Honor your father and mother"
Exodus 20:12

Call Mary Blessed
"...from now on all generatyions will call me blessed"
Luke 1:48

Mary is Our Mother in heaven
"Woman here is your son."
John 19: 26
"...Then he said to the disciple, "Here is your mother."
27

Mary shares her graces to all of us
"...for  you have found favor with God"
Luke 1:30

"He is not the God of the dead but of the living"
Mathew22: 32
thus if the saints are living in the presence of god truly can they not intercede for us. If often we might ask a friend to pray for us. How much more can the saints aid us by their prayer and intercession.

"If the dead are not raised at all, then why are they having themselves baptized for them?"
1 Corinthians 15:29

Prayers to Dead Saints are Powerful
"....the prayer of a righteous man is powerful and effective."
James 5:16
Thus, they pray to the mother of Jesus and to saints because they are among the most righteous people they know about.

Prayers For The Dead
" So now when you and Sarah prayed, it was I who brought and read  the record of your prayer before the glory of the Lord, and likewise whenever you bury the dead."
Tobit 12:12
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"May the Lord grant mercy to the household of Onesiphorus, because he often refreshed me and was not ashamed of my chain 17 -when he arrived in Rome, he eagerly searched for me and found me. 18 - may the Lord grant that he will find mercy  from the Lord on that day! And you know very well how much service he rendered in Ephesus. 2 Timothy 1:16-18 

Corinthians 15:29
We are even found to be misrepresenting God, that he raised Christ whom he did not raise if it is true that the dead are not raised.
16 For if the dead are not raised, then Christ has not been raised. 17 If Christ has not been raised your faith is futile and you are still in your sins 18 Then those also who have died in Christ  have perished. 19 If for this life only we have hoped in Christ, we are of all people most to be petied. 20 But in fact Christ has been raised from the dead the first fruits of those who have died. 21 For since death came through a human being , the resurrection of the dead has also come through a human being; 22 for as all die in Adam, so all will be made alive in Christ. 23 But each in his own order; Christ is the first fruits then at his comming those who belong to Christ. 24 Then comes  the end, when he hands over the kingdom to God the Father, after he has destroyed........ 29 Otherwise, what will those people who recieve baptism on behalf of the dead? If the dead are not raised at all, why are people baptized on their behalf?

Dead Saints Are Aware of Earthly Affairs
Matthew 22:30/Luke 15:10 1 Corinthians 4:9 / Hebrews 12:1

Dead Saints Intercede For Those On Earth
Jeremiah 15:1 / 2 Maccabees 15:14 / Revelation 6:9-10
Exodus 32:11

Moses Pleaded with YAHWEH saying " Do not bring this disaster on your people. Remember Abraham, Isaac and Jacob, your servants to whom by own self, you swore and made this promise." I will make your offspring as many as the stars of Heaven ". So YAHWEH relented and did not bring on his people the disaster he had threatened. . I will make your offspring as many as the stars of Heaven ". So YAHWEH relented and did not bring on his people the disaster he had threatened.

Saints Are Intermediaries And Present Our Prayers To God
Revelation 5:8

When he had taken the scroll, the four living creatures and the twenty-four elders hell before the Lamb, each holding a harp and a golden bowls full of incense which are the prayers of the saints.

Dead Saints Appear On Earth And Interact With Men
1 Samuel 28:12-15 with Ecc 46:20 / 2 Maccabees 15:13-16 Matthew 17:1-3 / Matthew 27:50-53 / Revelation 11:3
The Communion of Saints