This psalm is a lament of God over the sinfulness of humankind. It is a rueful expression of disappointment on God's part that there are none who care for the poor, call upon him in prayer, or do the good he calls for. On the one hand this is an overstatement, for we also see references to the poor and the righteous. They are not under the same judgment. On the other hand, even the righteous must repent daily for our thoughts and words leak out, showing an inner corruption from which we have not fully escaped. And sometimes, we must be numbered among those who do not do good. Sometimes our thoughts become words and our words lead to actions for which we must repent. We are among those who have turned aside.
Thank God we have a champion of righteousness! Our Lord Jesus Christ is the righteousness of God and our righteousness also by faith. Through his suffering and death our sins are forgiven. By his perfect life our faith puts us in the league of the righteous. For Jesus' sake we can both confess our sins, and rejoice in God's salvation. For it has come out of Zion. Our urgent need has been met. And we have been saved.