Because God is all knowing, He hears all things, including every prayer of every unbeliever or sinner. In addition to hearing their prayers, God offers several examples in the Bible of responding to the prayers of unbelievers.
Does God hear the prayer of an unbeliever?
A classic example found in the Old Testament includes the people of Nineveh in the book of Jonah. God had commanded Jonah to preach that the city would be destroyed in 40 days. When he did, the entire city responded with repentance, asking God to relent (Jonah 3:5-10). God spared the city, angering Jonah in the process (Jonah 4).
In the New Testament, Acts 10 shares the account of Cornelius, a Roman centurion who prayed to the God of the Jews. God responded to his prayers by sending Peter to preach salvation to Cornelius and those in his home.
Jeremiah 29:13 is a universal call to pray to God: "You will seek me and find me, when you seek me with all your heart."
However, there is one difficult passage regarding the prayers of unbelievers. It is found in John 9:31 and reads, "We know that God does not listen to sinners, but if anyone is a worshiper of God and does his will, God listens to him." Some have interpreted this passage to mean that God does not hear the prayers of unbelievers excepting one for salvation. Others argue that believers who pray while living in sin are not heard by God until they repent. But it is clear God hears all prayers, though He only answers according to His will. This is true whether the person is a devout believer, a "sinning" believer, or not a believer.
The difference is that believers in Christ, who have been redeemed by His blood and adopted into the family of God (Ephesians 1:3-10), can approach God boldly and with confidence that their prayers will be heard and answered according to God's perfect will (Romans 12:1-2; John 14:13). Hebrews 4:16 says, "Let us then with confidence draw near to the throne of grace, that we may receive mercy and find grace to help in time of need." James 5:16 even states, "The prayer of a righteous person is powerful and effective" (NIV).
While many of the teachings regarding prayer in the Bible are written to believers, God hears the prayers of all, responds to those who seek Him with all their heart, and calls believers especially to boldly come to Him with their prayers. He promises to both hear and answer according to His perfect will.
Is there a specific prayer of salvation?
Does God love everyone or just Christians?
Is God omniscient? What does it mean to be omniscient?
How is Jesus our High Priest?
Why pray? What is the purpose of prayer?
Truth about God