When Jesus spoke those words, He was not referring to the Traditional Latin Liturgy or any liturgy for that matter He was not saying anything about communion rails or whether the altar servers should be male or female.
To worship in spirit and truth is to live out our faith. It is to live out our baptismal promises and continually be renewed throughout our life through prayer, participation in the Sacraments of the Church, and service to others. When our worship of God is grounded in Spirit and Truth, our daily life begins to change because WE are being changed from the inside out. Changing the face of the altar by having communion rails, banning girls from being altar servers, and placing the tabernacle in the center does not change people. True Catholicism teaches that only the grace of God can change people.
The words "worship in Spirit and Truth" comes from the Gospel of John. In this historical story, Jesus breaks the Jewish custom of speaking to the Samaritan woman. As their conversation unfolds, the Samaritan woman tries to distract Jesus by making a reference to the existing rivalry among those who worship on the mountain, Gerizim, in Samaria, and those who worship in the temple in Jerusalem. However, Jesus was more interested in bringing the woman to conversion rather than entering a debate about WHERE God should be worshipped. He cuts through her diversion with the following (the bold is mine):
"Believe me,woman, the hour is coming when you will worship the Father neither on this mountain nor in Jerusalem. You people worship what you do not understand: we worship what we understand, because salvation is from the Jews. But the hour is coming, and is now here, when true worshipers will worship the Father in Spirit and truth; and indeed the Father seeks such people to worship Him. God is Spirit, and those who worship Him must worship in Spirit and truth."From this story, we learned that some people become so caught up in the logistics of worship that they miss the experience of being in communion with the One they came to worship. Like the Samaritan woman, they were more concern as to WHERE one should worship, where the tabernacle should be, where the flowers should be, where the crucifix should be, where the candles should be, etc. Jesus taught that true worship cannot be limited to certain conditions or places, be it Jerusalem (as the Jews believed) or Mount Gerizim (as the Samaritans believed) or even in the church building (as some Traditional Latin Catholics believed).
The "Spirit" in Jesus' reference is the Spirit given by God who reveals truth and moves one to worship God in truth and charity. To worship in spirit and truth in the Mass means to be guided by the Spirit who enables us to actively participate and to be fully attentive and consciously present to Christ the High Priest who is present to us in the gathered assembly, in the person of the priest presider, in the Word proclaimed and uniquely and substantially in the Eucharistic elements of Bread and Wine This is why in the Way, we often begin our celebration by telling the brothers to leave whatever problems they have outside and to be fully attentive and participate in the celebration. So, are we a people who worship God in spirit and truth or are we a people who constantly complain and grumble about everything? It is only when our hearts and minds are open to God's love and grace that we can ever hope to worship God in Spirit and in truth.