In the Gospel of John, we are giving three essentials. They are the “musts” of his Gospel. The first must is in Chapter 3 when he was speaking to Nicodemus. 
He said, “You MUST be born again.” A meaningful, satisfying relationship with God begins with the new birth. A time of spiritual renewal during which we place our confidence not in the flesh, but in God, and what He accomplished for us on the cross of Calvary. The second must is in verse 3:14, Jesus Himself said, “as Moses lifted up the serpent in the wilderness so the son of Man MUST be lifted up.” Jesus is the center of our confidence. It’s all about Him. The charge of born again believers is to always lift up Jesus. The third must comes in Chapter 4 when Jesus was talking to the woman at the well and said, “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.”
The “must” of worship is in spirit, not in the Holy Spirit. The definite article is missing in Greek. It was time, Jesus said, that as a result of His death and resurrection, the place of worship is no longer a physical temple, but rather it would be in man’s spirit. I believe we are Trinitarian beings just like God. We have a body, soul and a spirit. Worship must take part in man’s inner parts, his core of existence, that is, his spirit. Many people consider themselves to have worshipped because they’ve been to the right place at the right time. In Jesus day the right place was Jerusalem for the Jews and Samaria for the Samaritans. We often are confused as well and think that the right place is in a church building. If we have occupied a seat, or have sung a song, or have listened to a sermon then we have worshipped. Hopefully, those things are aids to our worship, but they are not worship in and of themselves. Our soul life, or feelings are not the true source of worship either. The soul is often referred to as the seat of our emotions. Emotions can be stirred by true worship. Tears may swell up in our eyes and joy might flood our hearts, but unfortunately, it is possible for these things to happen without true worship.
True worship only occurs when our spirit attunes with God, for God Himself is spirit. William Barclay has written on this point, “The true, the genuine worship is when man, through his spirit, attains to friendship and intimacy with God. True and genuine worship is not to come to a certain place; it is not to go through a certain ritual or liturgy; it is not even to bring certain gifts. True worship is when the spirit, the immortal and invisible part of man, speaks to and meets with God, who is immortal and invisible.”
Chuck
“Get out of here, Satan,” Jesus told him. “For the Scriptures say, ‘You must worship the LORD your God and serve only him.’” Matthew 4:10