"God is spirit, and those who worship Him must worship in spirit and truth.” (John 4:24)
Jesus said this to a Samaritan women at Jacob's well. From that conversation she came to believe that Jesus was the Messiah and went into town to tell her friends. Some of those friends came to the well to visit with Jesus and concluded:
"...we have heard for ourselves and know that this One is indeed the Savior of the world.” (John 4:42)
Jesus is still the Savior of the world, but when will the world be saved? It has been 2,000 years and the world is no more saved today than it was at that time.
"For all have sinned and fallen short of the glory of God...The wages of sin is death, but the free gift of God is eternal life through Jesus Christ our Lord." (Romans 3:23; 6:23)
"For if the dead are not raised, not even Christ has been raised; and if Christ has not been raised, your faith is worthless; you are still in your sins. Then those also who have fallen asleep in Christ have perished. If we have hoped in Christ in this life only, we are of all humanity most to be pitied.... But now Christ has been raised from the dead, the first fruits of those who are asleep. For since by a man came death, by a man also came the resurrection of the dead. For as in Adam ALL die, so also in Christ ALL will be made alive....so that God may be ALL in ALL....But someone will say How are the dead raised? and with what kind of body do they come?....It is sown a natural body, it is raised a SPIRITUAL body....Just as we have borne the image of the earthly, we will also bear the image of the heavenly." (1 Corinthians 15:16-49)
Only after every human has died and every human has been resurrected from mortal into an immortal will humanity worship God both "in spirit and truth".
Then every knee will have bowed and every tongue will have confessed that Jesus Christ is Lord to the glory of God the Father.
“For it is written, as I live, says the Lord, every knee shall bow to me, and every tongue shall give praise to God….of those who are in heaven and on earth and under the earth, and every tongue will confess that Jesus Christ is Lord, to the glory of God the Father. " (Romans 14:11; Philippians 2:10-11)
All humanity will then know that "this One is indeed the Savior of the world".
"Then I saw a new heaven and a new earth, for the old heaven and the old earth had disappeared. And the sea was also gone. And I saw the holy city, the new Jerusalem, coming down from God out of heaven like a bride beautifully dressed for her husband. I heard a loud shout from the throne, saying, “Look, God’s home is now among His people! He will live with them, and they will be His people. God Himself will be with them. He will wipe every tear from their eyes, and there will be no more death or sorrow or crying or pain. All these things are gone forever.” (Revelation 21:1-4)