Up to this point in Psalm 40 we have seen how the Psalmist has meditated upon the work of redemption and even spoken of it in the person of the Messiah. Now in verses 11-17 he enlarges and enhances the doctrine of his mediation between us and God, speaking in his own person. So at this point the Psalmist is encouraging us to come boldly to the throne of grace for mercy and grace.
Then in verse 11 we see the lament part of Psalm 40. There are certain elements found in lament throughout the Psalms. We first see an Invocation. The Psalmist cries out to God to listen in verses 11 and 13. In verse 12 we find the Complaint. The Psalmist tells God what he believes is wrong. Then in verses 13-15 comes a Petition, with the Psalmist expressing what he wants God to do for him. Following that comes an Expression of Trust, (v. 17) where the Psalmist recounts what God has done in the past, showing his hope that God will act again. Finally, the last element found in a lament is an Expression of Praise, (v. 16) where we find the Psalmist celebrating the goodness, mercy, grace, and sovereignty of Holy God!
At different times these elements can be found in our own personal and community experiences of worship. In verses 10 and 11 we see the Psalmist saying that God's faithfulness and steadfast love are told to everyone in the great assembly, which includes all, so that His mercy and grace are passed from one generation to the next in worship! Are we sufficiently aware today that in how we worship we are passing the story of His faithfulness and steadfast love from generation to generation? We certainly need to be aware of the importance of the way we worship - "that all may see and fear and put their trust in Him!" mjm