How do we know the promise of grace is for all sinners?

The Scriptures repeatedly affirm God's readiness to extend grace and mercy to returning sinners. In 2 Chronicles 30:9, we learn that if we return to God, He will not turn His face from us. This notion is echoed in Jeremiah 3:12, where God invites His people to come back, promising not to remain angry forever due to His mercy. Additionally, Joel 2:13 and Isaiah 55:7 further stress that no matter how wicked we might perceive ourselves, God is gracious and willing to pardon as we genuinely turn to Him. The examples of notorious sinners like Manasseh, who sought God and received mercy, serve to comfort any believer who doubts their own forgiveness.