By "sinners" in this question, we mean unsaved unrepentant sinners. Here's the answer---Generally, though there maybe exceptions, God does not hear the prayers of unrepentant sinners.
Isa 1:15 When you spread out your hands, I will hide My eyes from you; Even though you make many prayers, I will not hear. Your hands are full of blood.
Pr 1:28 "Then they will call on me, but I will not answer; They will seek me diligently, but they will not find me.
Pr 1: 29 Because they hated knowledge And did not choose the fear of the LORD,
Mic 3:4 Then they will cry to the LORD, But He will not hear them; He will even hide His face from them at that time, Because they have been evil in their deeds.
Isa 59:2 But your iniquities have separated you from your God; And your sins have hidden His face from you, So that He will not hear.
To a man who has heard the Gospel and rejected it, here's what God has to say about him:
Heb 10:28 Anyone who has rejected Moses' law dies without mercy on the testimony of two or three witnesses.
Heb 10:29 Of how much worse punishment, do you suppose, will he be thought worthy who has trampled the Son of God underfoot, counted the blood of the covenant by which he was sanctified a common thing, and insulted the Spirit of grace?
Most assuredly, though, the prayer that God hears from a sinner is the cry of repentance.
