"Yet a time is coming and has now come when the true worshipers will worship the Father in the Spirit and in truth, for they are the kind of worshipers the Father seeks. God is spirit, and his worshipers must worship in the Spirit and in truth.”
The Old Testament Law prescribed how to worship. This is what the Samaritan woman was alluding to when she said, "Our ancestors worshiped on this mountain, but you Jews claim that the place where we must worship is in Jerusalem.”
According to both tradition and Law, if at all possible, people were supposed to go to the Temple in Jerusalem during the holy days and make sacrifice at the Temple. There were all sorts of sacrifices and reasons to make them. There were grain sacrifices and oil sacrifices and animal sacrifices ranging from small to large (doves, goats, lambs, cattle, etc.). Smaller sacrifices could be made to give thanks and show gratitude. Larger sacrifices were made for the atonement of sin. Sacrifices could also be made to seal vows. And once a year a priest would enter the Holy of Holies, the Most Holy Place, and make a special sacrifice for the sin of the entire nation of Israel.
Making sacrifices at the Temple was a ritualistic act of worship that the Law demanded. It might engage the emotions and the spirit, or it might not; since it was the Law, it didn't really matter as long as the sacrifice was correctly made.
But everything changed when Messiah came. Jesus claimed that the entire Law was fulfilled (accomplished brought to completion) in Him. The Old Testament laws were never God's ultimate plan. Because the Law was fulfilled in Christ, there is now a new freedom in worship that is not about a location or a ritual. This new worship is what God has always desired.
This new, authentic worship that God is seeking involves our emotions (spirit) and our minds (truth). It is not about where we are, it is about who we are. It is about consciously and intentionally giving our whole selves to Him. This can be done any time and any place. It happens as we sing to Him. It happens as we pray. It happens as we lie in bed at night and think of Him. It happens as we give water to a thirsty person or food to the hungry or a blanket to the poor and cold. Authentic worship happens wherever in spirit and truth we are aware of God's presence with us and we realize His love. It is real. it is intimate. It is meaningful.