Psalm 32, The Blessedness of Forgiveness - imputed righteousness by faith

1 Blessed is he whose transgression is forgiven,whose sin is covered.
2 Blessed is the man unto whom the LORD imputeth not iniquity,-Rom. 4.7, 8
and in whose spirit there is no guile.
3 When I kept silence, my bones waxed old through my roaring all the day long.
4 For day and night thy hand was heavy upon me:my moisture is turned into the drought of summer.
5 I acknowledged my sin unto thee,and mine iniquity have I not hid.I said, I will confess my transgressions unto the LORD;and thou forgavest the iniquity of my sin.
6 For this shall every one that is godly pray unto thee in a time when thou mayest be found:surely in the floods of great waters they shall not come nigh unto him.
7 Thou art my hiding place;thou shalt preserve me from trouble;thou shalt compass me about with songs of deliverance.
8 I will instruct thee and teach thee in the way which thou shalt go:I will guide thee with mine eye.
9 Be ye not as the horse, or as the mule,which have no understanding:whose mouth must be held in with bit and bridle,lest they come near unto thee.
10 Many sorrows shall be to the wicked:but he that trusteth in the LORD, mercy shall compass him about.
11 Be glad in the LORD, and rejoice, ye righteous:and shout for joy, all ye that are upright in heart.

Gods promise to Abraham - 'in you all the nations will be blessed' - refering to the same blessedness David was talking about, which is imputed righteousness by faith.