Final answer:
John 4:21 speaks about a time when worship would no longer be confined to specific sacred places, symbolic of a new era of spiritual worship. This passage is a small part of the Christian belief system that also includes the concept of the Second Coming of Jesus, which was significantly focused upon by various religious sects in the mid-nineteenth century.
Step-by-step explanation:
According to John 4:21, the time that is coming is a future period when true worshippers will worship the Father in spirit and truth, a reference to a new era of spiritual worship that breaks away from the traditional worship practices of specific places, like the city of Jerusalem. This passage foreshadows the Christian understanding of the change in how people connect with God, which was brought about by the life and teachings of Jesus Christ. This concept aligns with the broader religious narrative of the Second Coming of Jesus, as discussed during the mid-nineteenth century by various millennial sects like the Mormons, Shakers, and the followers of William Miller who anticipated the imminent return of Christ and prepared for this event in various ways.