If we’re children of Christ and we stand before the judgment seat of God on the last day and God says to us, “You’re covered by the blood of my Son, and it’s a good thing, because you did this, this, this, this, and this,” we won’t say, “But, Lord, I did this in Your name, I did that in Your name. You really aren’t being fair.” However, there will be many who will respond in just that manner. Jesus is going to say to those people, “Please leave, I don’t know who you are.” A person who trusts God trusts not only His promises but His judgment. Even in a prayer of contrition, such a person acknowledges that God would be absolutely justified to destroy him for his sin. You can never come to God’s church, come to the Lord’s Table, thinking that God owes you something. If you do, you’re better off not to pray, not to commune, because you are blaspheming and slandering the Giver of every good and perfect gift, Who has treated you only with mercy.
-R.C. Sproul, A Taste for Heaven: Worship in the Light of Eternity