The Samaritan woman was talking with Jesus about worship, John 4:19-24--

“The woman said to Him, ‘Sir, I perceive that You are a prophet. Our fathers worshiped in this mountain, and you people say that in Jerusalem is the place where men ought to worship.’”
“Jesus said to her, ‘Woman, believe Me, an hour is coming when neither in this mountain nor in Jerusalem will you worship the Father. You worship what you do not know; we worship what we know, for salvation is from the Jews. But an hour is coming, and now is, when the true worshipers will worship the Father in spirit and truth; for such people the Father seeks to be His worshipers.’”
“‘God is spirit, and those who worship Him must worship in spirit and truth.’" NASU

Worship in spirit is a reference to what is taking place in the inner man. Our own spirit interacts with the Spirit of God given to us as a down payment on our eternal inheritance in Jesus Christ. As Paul wrote to the Ephesian Christians, Eph 3:14-21—

"Behold, days are coming," declares the LORD,
“For this reason I bow my knees before the Father, from whom every family in heaven and on earth derives its name, that He would grant you, according to the riches of His glory, to be strengthened with power through His Spirit in the inner man, so that Christ may dwell in your hearts through faith; and that you, being rooted and grounded in love, may be able to comprehend with all the saints what is the breadth and length and height and depth, and to know the love of Christ which surpasses knowledge, that you may be filled up to all the fullness of God.”
“Now to Him who is able to do far more abundantly beyond all that we ask or think, according to the power that works within us, to Him be the glory in the church and in Christ Jesus to all generations forever and ever. Amen.” NASU

It is when our own spirit is in submission to the Spirit of God that we are able to have the right “spirit of worship.” This worship is not restricted to what is done in the assembly of the church, but includes what we do each day of our lives. Jesus’ teaching on worship is not directed to a time or place, but to truth and spirit. This is life instruction, not just church meeting instruction. Of course, life instruction includes church assembly, which is a vital part of life in Jesus.

We need to constantly remind ourselves of the nature of the new covenant, Jer 31:33-34--

"But this is the covenant which I will make with the house of Israel after those days," declares the LORD, "I will put My law within them and on their heart I will write it; and I will be their God, and they shall be My people.”
"They will not teach again, each man his neighbor and each man his brother, saying, "Know the LORD,' for they will all know Me, from the least of them to the greatest of them," declares the LORD, ‘for I will forgive their iniquity, and their sin I will remember no more.’" NASU

Worship in spirit is from the heart, the inner man. Indeed, our very reason for study of God’s word is so that our inner man can be edified, 1 Tim 1:5—

“But the goal of our instruction is love from a pure heart and a good conscience and a sincere faith.” NASU

The foundation for worship in spirit is to love God with all our being, and to love our neighbor as ourselves. Love is the bond of perfection that binds us together, to God and to each other. God is love.

Ritual acts of worship motivated by fear and sense of duty are not what Jesus wants from us. When we worship God from the heart because we love Him, we are worshipping in the spirit that Jesus desires.