In verses 8 and 9 David reflects on the character of God. No doubt, the psalmist is drawing on his own experience of God but I also think he is aware of different ways in which God helped his people in previous generations. And his words have been used by all subsequent generations to express their praise, are used today and will be used in the future. David wrote them in Hebrew but we use his words in English and other peoples use them in their languages. Clearly his words highlight the unchangeable nature of God.
The Lord does not treat his people the way their sins deserve. Instead of punishment they receive mercy in various ways. Surely here we have a very strong indication regarding the main focus of our worship. While it is good to praise God for his holiness and to praise him for his wonderful act of creation and amazing control in providence, the unique feature of grace is that the Lord is full of mercy. He shows mercy at the natural level in supplying the physical and other needs of his creatures. More importantly, he forgives his people their sins. This was the story of David’s life, it was the story of David’s friends, it was the story of God’s people who preceded David, and it is the story of all of God’s people who have succeeded David.
The psalmist delighted in thinking about God’s grace and mercy, his slowness to anger and his abounding in steadfast love. David mentions them together in two other psalms (86:14-16; 103:8). In Psalm 25:6, he looks back into history and sees God’s mercy: ‘Remember your mercy, O Lord, and your steadfast love, for they have been from of old.’ God had heard David’s cry for mercy (Pss. 28:6; 31:22; 116:1). Therefore he could sing, ‘Surely goodness and mercy shall follow me all the days of my life, and I shall dwell in the house of the Lord for ever’ (Ps. 23:6).
David returns to thinking about the future in verses 10-13. He touches upon the responsibility of his people to tell others about the mighty deeds and splendour of God’s kingdom, including its endlessness. Obviously, believers have the same role in every generation – tell others about their God. David could speak about God’s great works for Israel, but we can also speak about God’s great works through Jesus his Son. It is impossible for us to work out how much David knew when he penned this description of the calling of God’s people. I wonder what he would say if he were told how much we have the privilege of saying about the kingdom of Christ.