Psalms 73:9

They set their mouth against the heavens, and their tongue walketh through the earth.

In Psalm 73:2-17 David looks on the prosperity of the wicked and is tempted to doubt God. His trouble comes from his separating himself from God, not from God separating Himself from him, and God is not to be blamed for anyone's backsliding.

The verse portrays the seemingly prospered wicked setting themselves in arrogance against heaven while their speech spreads across the earth. In the words that follow they ask whether God knows what they do, confident that He is unaware. That confidence is false, for God sees their deeds and will not remain silent forever, but will rebuke them and confront them with those deeds.

Their apparent success does not mean safety, for God rejects the course of those who forget Him, and His blessing will not rest on them. Forgetting God even for an hour or a moment puts a person on a dangerous path whose perils may go unrealized until habit binds him as firmly as iron and keeps him enslaved to the evil he has dabbled in. Only those whose hearts are fortified with pure principles are safe, maintaining a constant battle against the selfishness and corruption of the human heart. Workers who become careless and inattentive to their eternal interest suffer great loss, as the tempter gains access and leads them into uncertain paths.