There is some very important insights concerning worship in the Psalms. Not only do the Psalms remind us that God is ruler and creator over all creation, but it also that God has revealed himself to us so that we can know, love, worship and serve him. They also remind us God acts in history on behalf of his people, telling us something of the kind of God he is so that we can respond accordingly. They remind us that we have two choices in life: Be faithful to God and receive his blessings, or be disloyal and receive curses.
The Psalms are also a model for how to worship, pray, and reflect on God and the nature of our relationship with him. Psalm 51 provides a model for prayer and gives some important insights concerning worship.
David recognizes the depth of his sin with Bathsheba and Uriah, which included adultery, deceit, and murder. He recognized how much it affected his relationship with God and gives these insights.
1. God is not interested in mere acts of worship themselves. In verse 16, David says, "You do not delight in sacrifice, or I would bring it, you do not take pleasure in burnt offerings." David could have went through the prescribed rituals, such as offering up the sin offering, but he knew that this in itself was not what God was after. In Isaiah, God clearly did not accept mere "rituals." In chapter 1, he refers to it as "trampling of my courts." God doesn't "need" meat offered on an altar. In fact, David's sins were capital offenses, so really there was nothing David could have done to appease God anyway.
2. God is interested in a pure heart. David understands that God wants a loyal, dedicated, and faithful heart, not a sacrifice. This is why David goes on to say in verse 17, "The sacrifices of God are a broken spirit, a broken and contrite heart, O God, you will not despise." This is why David had been praying in verse 10, "Create in me a pure heart, O God, and renew a steadfast spirit within me." All David could do was come in the honesty of his heart, appeal to God's mercy and be open to allowing God to change his heart. What David needed was forgiveness and repentance which amounts to a change in heart, mind, and actions.
3. Worship from a pure heart is delightful to God. This Psalm does not teach that God never wants any kind of prescribed worship. The last verse says, "…Then there will be righteous sacrifices, whole burnt offerings to delight you…" But God does not delight in the sacrifices and worship itself, but in the heart that offers up the worship. When the heart, lifestyle, thoughts, and actions all are a reflection of the worship offered to God, then God truly delights in it.
So, when our lives during the week reflect what we sing, pray, and declare in our worship times, then God truly delights in our worship we offer to him out of the integrity of our hearts. Worship is truly connected to what we do, say, and think every day.