"Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience and our bodies washed with pure water."
When believing churchmen approach God in prayer, in and through the merits and atonement of Jesus Christ alone--and all by faith--then they should come to Him with great confidence. And, why not? Our Redeemer has done it all for us, and He is seated in heaven. There is no reason at all for us to be either doubtful or fretful.
But if we presume to come to God in our own righteousness, or on the basis of our works, or merits--then, on the other hand, we ought to fear and quake. Why? Because God will (rightly) reject us, and cast us from His presence.
[Puritan quote of the day: "The creature may have the milk of our love, but we must keep the cream for God. He who is above all, must be loved above all." --Thomas Watson, in, "A Body of Divinity"]