Worship is a life response to the object of our worship. We worship God in spirit and truth when we recognize God alone is worthy of our praise and declare it with our attitudes, actions, and words.
John 4:23–24 records Jesus saying, "But the hour is coming, and is now here, when the true worshipers will worship the Father in spirit and truth, for the Father is seeking such people to worship him. God is spirit, and those who worship him must worship in spirit and truth." First, it is important to understand what worship is. Many equate worship with singing music in church. This is one aspect of worship (Psalm 100:2), but worship is in no way limited to song. It is a full life response to the object of our worship. When we truly worship something, it presumes an attitude of reverence. When we worship God, we recognize God for who He is and what He does and give our lives to Him. It is important to note that we worship in spirit and in truth simultaneously. To worship God in spirit and in truth is to declare that God is worthy of our reverence.
One way to understand worship is to think of it as "worth-ship." The Greek word used for "worship" implies an attitude of reverence, including physical gestures such as kissing the hand or kneeling (Psalm 95:6). We worship something when we act as if it has value. Sometimes our worship is focused on that which is actually worthy of reverence (like God). Other times it is misdirected (for instance, we worship our work or our bank accounts or fashion or a political icon).
Our attitudes and actions reflect that we believe the character and conduct of God to be worthy of praise and adoration. At times, our worship is expressed through corporate singing, teaching, and giving. It is also expressed in our daily lives through prayer, Scripture reading, acts of kindness, gratitude, pure thoughts, and the like. Our spirit is the core of who we are; it is the center of our volition and our emotions. To worship in spirit is to do something that is beyond the physical.
Worshiping in truth includes the truth about who God is and what He does, hence why He is worthy of worship. It includes the truth about our circumstances: when we are experiencing heartache, or conversely, in our joyful circumstances. Truth itself can be a means of worship; we worship God when we declare His truth.
We worship God both through our emotional core and in light of reality. We worship God based on the truth of who He is, the truth of who we are, the truth of what God does, and the truth of what is going on in our world. We do it with a heart inclined toward God and in submission to Him. We worship God when our attitudes, actions, and words declare that He is worthy of our praise.