The last Psalm was a Hymn of Thanksgiving, this one is a Psalm of Thanksgivingwritten by David just when he assumed the throne, when he was about to become king over all Israel and Judah. Its title is, "A Psalm of David." This is what he said to himself: "I will sing". In the one hundredth Psalm, he had exhorted other people to sing, now, in the hundred and first, he declares what he will himself do: "I will sing of mercy and judgment" (v. 1). The vow in Psalms 101:1 suggests not merely a pious but a royal singer, while, more definitely still, the form which it finally assumes in 101:8 argues a theocratic king.
Accordingly, after he details his essential character by recording his resolves to act uprightly, first in personal conduct and domestic life (v. 2), then with reference to his associates (v. 3~5), and finally in his obligation to keep watch over his subjects, servants, and the inmates of his house (v. 6~7), Psalm 101:8 places the exercise of the punitive power vested in rulers in special relation to the city of God. As the city must not only have impressed upon it the character of holiness in its public worship, but must also exhibit that character in its moral results (Isaiah 35:8; 52:1; Nahum 2:1). David vows that he will exercise his royal power in the service of God in order to realize this end.