God is spirit, and his worshipers must worship in spirit and in truth.
Jesus was speaking to the Samaritan woman as He said this statement. The Samaritans had a problem. They were very vibrant in their worship but they were off-base on who or what they were worshipping. It doesn’t matter what our intention is or how spirited our worship is if it is pointed in the wrong direction.
The Jews of Jesus day had just the opposite problem. They had the truth but no spirit. The Pharisees had reduced their religion into a bunch of rules: do this, don’t do that. The leaders were off base in their understanding of the rules but even if they weren’t they had sucked the joy out of worship.
Although this is admittedly an oversimplification, the church has fallen into one of these two camps. There are churches where everything is a party and feelings are emphasized. The truth in the Word of God is not the central part of a worship service.
On the other hand, some churches emphasize strict Bible teaching and doctrine and have no joy in their salvation. Yes they are saved but you wouldn’t be able to see the difference in their lives by how excited their salvation makes them.
As individuals and churches we need to emphasize balance. There is a place for joyful singing and dancing and there is a time for solemn biblical reflection. We should worship in both spirit and in truth.