He saved us, not because of righteous things we had done, but because of his mercy. He saved us through the washing of rebirth and renewal by the Holy Spirit. – Titus 3:5
God's mercy is poured out on those who put their faith in Christ. Mercy is not getting what you deserve. Because of His mercy, you can live in right standing with God. You don' have to live trying to please God. Through His mercy, He is already pleased.
His mercy is renewing your mind and your heart. Salvation is not about what you do for God, but about what He has done for you.