v1, Children and Adults have one big contrast in faith, the ability to wait. Adults can wait when they trust God to hear them and answer. Whereas children can not wait, so when adult believers show God patience in their requests to the point of crying, God responds! It is not just a mark of maturity, but it proves to yourself and our God, that we love His will more than our own will.
v2, “The LORD is my rock and my fortress and my deliverer” A rock was helpful to the ancient people of the east in three ways.
- It could provide essential shade, needed in the merciless sun and heat of the desert (as in Isaiah 32:2). It’s shade was a soothing solace.
- Huge rocks can provide safe shelter from damaging winds, It could provide shelter and protection in its cracks and crevasses (as in Exodus 33:22 and Proverbs 30:26).
- It could provide a firm place to stand and fight, as opposed to sinking sand (as in Psalm 40:2). David saw his God as his strength reminding us of the promise of secure safety, later expressed through Paul: Ephesians 6:10.
v3, The new song is sung because The Lord’s presence brings refreshing expressions of joy in victories over temptations of their sin, this rejoicing can help bring other people out of their sin and into a right relationship with Christ, Revelation 5:9 & 14:3.
v6-8, “Sacrifice & offering You did not desire, my ears you have opened”, David’s surrender to God was wonderful and an impressive example. Yet he only foreshadowed the ultimate submission to God carried out by the Messiah, Jesus Christ. Hebrews 10:5-10 quotes the Septuagint (ancient Greek) translation of Psalm 40:6-8. This is a wonderful and remarkable prophecy of the work of Jesus. It shows God’s ultimate dissatisfaction in animal sacrifices, looking forward to a Perfect Sacrifice, because he didn’t desire them, Jesus willingly committed himself because it was what The Father desired. It shows that God the Son came in a prepared body (the Septuagint reads, But a body You have prepared for Me, Hebrews 10:5 and through to v7. God made and gave the best unique body to sacrifice that he could! v9, “I have proclaimed the good news of righteousness in the great assembly”, This was part of the new song and praise that came from his deliverance. David did not hold his praise back, it was PROCLAIMED. Yet, as in the previous verses, this has a far greater and perfect fulfillment in Jesus, the Son of David. It was true of Jesus in His earthly ministry. “This is what Jesus can say. He was the Princely Ruler of open-air preachers, the Greatest Itinerant of all preachers.” It is also true of Jesus in eternity to come, in the midst of the assembly I will sing praise to You (Heb. 2:12 fulfilling Psa. 22:22). It’s remarkable to think of Jesus leading the assembly of God’s people in praise to God the Father!