Here, 1. David praises God's goodness and gives him the glory of it:
Thou art good and doest good. All who have any knowledge of God and
dealings with him wilt own that he does good, and therefore will
conclude that he is good. The streams of God's goodness are so
numerous, and run so full, so strong, to all the creatures, that we
must conclude the fountain that is in himself to be inexhaustible. We
cannot conceive how much good our God does every day, much less can we
conceive how good he is. Let us acknowledge it with admiration and with
holy love and thankfulness. 2. He prays for God's grace, and begs to be
under the guidance and influence of it: Teach me thy statutes. "Lord,
thou doest good to all, art the bountiful benefactor of all the
creatures; this is the good I beg thou wilt do to me,--Instruct me in
my duty, incline me to it, and enable me to do it. Thou art good, and
doest good; Lord, teach me thy statutes, that I may be good and do
good, may have a good heart and live a good life." It is an
encouragement to poor sinners to hope that God will teach them his way
because he is good and upright, Ps. xxv. 8.