Psalm 40 gives thanks to the LORD for past mercies and then presents a new situation that has risen in which the singer is again in need of God’s mercy.    

1-10 – The singer recounts past mercies from God that he is thankful for.  The singer recounts these past mercies to those in the great congregation.  In doing so, the singer highlights the LORD’s attributes of faithfulness and steadfast love.  The singer goes on to say blessed is the man who makes the LORD his trust; such a man will not be disappointed.  The LORD does not seek sacrifice and offerings from his people, but an open ear to hear and to respond to the word of the LORD.  

11-17 – The singer now asks for mercy once again from the LORD; he asks for deliverance from the wicked.  This deliverance would put the wicked to shame, and they would be disappointed in their schemes.  This is in contrast to the faithful, to all who seek the LORD; they should rejoice and be glad, shouting Great is the LORD!  The prayer is offered in humility.