"After these things the Lord appointed seventy others also, and sent them two by two before His face into every city where He Himself was about to go. Then He said to them, 'The harvest truly is great but the laborers are few; therefore pray the Lord of the harvest to send out laborers into His harvest. Go your way; behold, I send you out as lambs among wolves. Carry neither money bag, knapsack, nor sandals; and greet no one along the road.'"
The Apostle John heard the loud voice of "...a great multitude in heaven..." [Revelation 19:1]. These are they who, from the beginning of time on this earth, were saved by the blood of the Lamb.
But there is another multitude; those that are lost either because they ignored or rejected God's call to salvation. No one will be lost because they did not know. In the great controversy between Christ and Satan everyone will have a choice; every person who has ever lived possessed the ability to think and choose will know; and if not by preaching, then by the voice of the Holy Spirit in their inmost heart. It has to be that way lest Satan charge God as being arbitrary and changeable. God does not change.
"And greet no one along the road"
That sounds odd, don't you think? to "greet no one along the road." I've thought about that and Christ is telling them not to loiter along; stopping to chit-chat about this and that, but to stay focused on the mission. Satan is always ready to distract us from the gospel commission and our mission on this earth during our days. Time is too short to spend it discussing the wants and ways of the world because there is danger in the becoming our ways.
Pray the Holy Spirit will send reapers, for the harvest is truly ripe.