"If I regard iniquity in my heart, the Lord will not hear me".
Every Christian knows that sin separates the Sinner from God. But sin separates the Christian's conscience from God as well . . if he regards it.
Remember the story of Balaam who goes up to the top of the mountain to curse Israel, the people of God? God lines Balaam out and sends him down the mountain to report back to Balaak the king:
"He (the LORD) hath not beheld iniquity in Jacob, neither hath he seen perverseness in Israel: the LORD his God is with him, and the shout of a king is among them" (Numbers 23:21).
Now obviously Jacob (Israel), just like you and I, was guilty of sin just as the nations that surrounded her. Yet here is one of the earliest unmistakable references to God's intention with His people; His intent to hold them guiltless, to regard them as innocent.
"God will provide himself a lamb" Abraham says to his son Isaac in Genesis 22:8. Abraham believed God and it was counted, or reckoned unto him as righteousness, just as we believe God in the matter of Christ being that lamb, and our faith is counted as righteousness. In Acts 15:9 Peter ends his argument before the elders of the brand-new church by telling them that God had put no difference between Jew and Gentile,"purifying their hearts by faith".
Our hearts are purified by faith, not constant introspection and endless vows to do better. Only when we believe Christ will we cease to regard our sin.
If you have failed and confessed your sin, do not regard it. Regard Christ who became sin for you dead on the cross. It is the only way to peace, it pleases God and it purifies your heart. Isn't He wonderful?