4:2 David's enemies stand in contrast to God; they were sinners, but He was righteous. If they were Absalom and his followers, or whoever they were, they were trying to turn David's honor as a godly king into a bad reputation with their lies (cf. 2 Sam. 15:3). "Deception"(NASB) refers to their lies and is preferable to the NIV translation "false gods."David's questions reflect his amazement at their foolishness.
4:3 David was godly (Heb. hasid) because he was the object of God's election for a special purpose. His godliness was the result of God's calling, not the reason for it. Because the Lord had set him aside for a special purpose of His own (i.e., sanctified, "set apart,"him) David was confident God would hear his prayer.
4:4 David urged his enemies on the basis of his calling by God (v. 3) not to give way to sin in their anger against the king (cf. Eph. 4:26). They would be wise to remain still as they meditated on their opposition to David while lying in bed at night rather than getting up and opposing him. Opposing the Lord's anointed would constitute sin. It would be better for them to submit to God by submitting to His agent, King David.
4:5 Righteous sacrifices are those offered with a proper spirit of submission to God and His king (cf. 2 Sam. 15:12). Rather than opposing, David's adversaries should trust.
