David called out to God and made supplication to Him (v. 8). He said that there was no profit to God if he went down into the pit. He also said that there was no praise and no declaring of God's faithfulness from the dust (v. 9). David was calling out to God, making prayers to God, and reminding God that if he died and went into the pit, there would be no praise to God and no declaration of God's faithfulness. For this reason he said that God should keep him alive. According to David's concept, it seemed that God owed him something.
David asked God to hear him and be gracious to him to be his help. He also thanked God for turning his mourning into dancing and loosening his sackcloth to gird him with rejoicing, that his glory (spirit) might sing psalms to God without silence and praise God forever (vv. 10-12).
I hope that by reading these psalms we can see that there is no comparison between the Old Testament economy and God's New Testament economy. The Old Testament is the old covenant, and the old covenant was based upon the law. The psalmists were very pious. They loved the law, uplifted the law, and treasured the keeping of the law to the uttermost. Many of the psalms were based upon the principle of keeping the law. The keeping of the law was the basic factor and structure of their composition.
But in Jeremiah 31 God told His fallen, degraded elect, the children of Israel, that He would make another covenant, a new covenant, which would not be based upon the law of letters, but upon a living law which God would write into their being (vv. 31-34). We are enjoying this new covenant today. The living law, the law of life, being written into the New Testament believers is to have God imparted into them. Thus, God in them is the law of life. In the new covenant, we who were once dead have been enlivened, resurrected from the dead, and regenerated to become a new person. After our regeneration, God continues to renew us, to sanctify us, to transform us, to conform us, and eventually to glorify us at the second coming of Christ.
There is no comparison between the old covenant of the Old Testament and the new covenant of the New Testament. The Psalms, therefore, are full of expressions that are not uttered in the New Testament, especially in the apostle Paul's Epistles. In 1 Corinthians 1:9, Paul said that God called us into the fellowship, the participation, of His Son. We have been called by God to partake of Christ, to enjoy Him. Thus, Christ becomes our life, our nature, and even our person. By God's salvation in the New Testament, we have been made one with Christ. According to the Lord's speaking in John 15, we believers and Christ are one tree. He is the vine tree, and we are the branches. Thus, all of us are one with Him, and we grow together with Him. Christ and we are all one person because He is the Head and we are the Body. The Head and the Body are not separate but are one person. We Christians are one with Christ.