“Dear children, this is the last hour; and as you have heard that the antichrist is coming, even now many antichrists have come. This is how we know it is the last hour.”
1 John 2:18

Those living and teaching in opposition to Christ have come and are coming. There is more than one. There is a stark contrast between the purity and innocence associated with children and the darkness associated with the antichrists. It is not pleasant, but we are called to live with a degree of urgency and awareness.