Worship is a response to God's mercy. In view of all that God has done for us in Christ Jesus, we are to turn ourselves over to God for Him to use as He chooses that His name maybe glorified among the nations. Our lives are to be surrendered to God as a gift of loving gratitude.
We are to offer to God a holy life that is not conformed to this world but is transformed by daily setting oneself apart from sin and, out of love, setting apart one's thinking and actions to the thinking and actions of God. Worship is the response of a life that gives glory to God in all one thinks and does.
Paul summarizes this in Romans 12:1-2 "I urge you therefore, brethren, by the mercies of God, to present your bodies a living and holy sacrifice, acceptable to God, which is your spiritual service of worship. And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what the will of God is, that which is good and acceptable and perfect."
The writer of Hebrews 13:15-16 states, "Therefore, by Him, let us continually offer the sacrifice of praise to God, that is, the fruit of our lips, giving thanks to His name. But do not forget to do good and to share, for with such sacrifices God is well pleased."
The singing of songs serves two purposes: to express one's loving thanks, praise, and commitment to God and to teach about God and His commands. Music, in and of itself, is not worship but simply one avenue for worship. As Mike leads people in singing, he leads them to respond, not just in the moment with their voices, but with a commitment of their lives day by day to God.