According to Scripture, praying to Mary is not only wrong but a detestable and idolatrous practice.
First, the Bible never implies, instructs, or commands believers to pray to Mary or any other human (aside from Jesus, who was and is God manifested in the flesh). It directs believers to exclusively pray to God (Matthew 6:9-13; Luke 11:2-4; John 14:12-14; John 17:1-26; Acts 7:59-60; 1 Corinthians 1:2; 1 John 5:14-15).
Additionally, God issued a severe warning in Leviticus against consulting, contacting, interrogating, or communicating with the dead, which includes praying to Mary or any other deceased human. In Leviticus 18:10-12, the Hebrew word for "contacting or consulting the dead" is “necromancy” and was named among other detestable activities like witchcraft and sorcery. These passages state:
“Let no one be found among you...who practices divination or sorcery, interprets omens, engages in witchcraft, or casts spells, or who is a medium or spiritist or who consults the dead [“necromancer”]. Anyone who does these things is detestable to the Lord; because of these same detestable practices the Lord your God will drive out those nations before you.”
Second, Mary was not a divine being, redeemer, or co-redeemer but a created being who was not without sin. Mary needed and trusted God as her Savior, which she confirmed in Luke 1:46-47 by proclaiming, “My soul exalts the Lord, and my spirit has rejoiced in God my Savior.” The only reason Mary was called blessed in Scripture (Luke 1:28, 42, 48) was that God chose her to supernaturally conceive and carry Jesus in her womb, which was an act of His unmerited favor (Matthew 1:18-20).
Third, Mary was not a mediator, co-mediator, or intercessor between God and humanity, Jesus and humanity, or Jesus and God. Scripture affirms only one Mediator between God and mankind —Jesus Christ (1 Timothy 2:5; Hebrews 7:25). It also appoints the Holy Spirit to the role of Intercessor, not Mary (Romans 8:26-27; John 16:7-11; John 16:13-15; John 14:26).
Therefore, since Mary was not divine nor a redeemer, mediator, or intercessor in any respect, praying to her is detestable and idolatrous because:
It results in consulting or contacting the dead, which is strictly forbidden and abhorred by God.
It improperly elevates Mary to an exalted status that exclusively belongs to God (Father, Son, and Holy Spirit).
It presumes that Mary—a redeemed sinner—holds power or influence over what God does or does not do, which undermines God’s supremacy, omnipotence, omniscience, and sovereignty, among other things.
It demotes Jesus from His rightful place as Mediator and the Holy Spirit from His divine role as Intercessor by unjustly placing Mary in those esteemed roles and positions.
I hope this information helps you understand why praying to Mary is not only wrong but a detestable and idolatrous practice that believers must avoid at all costs, renounce if practiced, and help others recognize its dangerous implications.