It was not merely a call to do this work, but a command. It has a two fold purpose....
1) It is a message of salvation to those who respond to it positively. Like those in the first century, when they heard it from Jesus, they just knew in their hearts that it was the truth and they became his disciples. Those disciples were then instructed to make more disciples by offering that message to others. (Matthew 28:19-20; Matthew 10:11-14) So it was never designed to convert the world, but rather to gather the "sheep" into one pen. Like Noah was instructed to gather righteous ones into the ark. He offered salvation to the people but they didn't listen. The only righteous people on earth at that time were Noah and his family.
2) The message itself acts as a warning to those who refuse it. Jesus said that his return would see the same kind of circumstances that were seen in Noah's day....a world filled with satanically influenced violence and immorality.
Noah had an assignment from God to save himself and his family when God determined to destroy that world of ungodly people. (Matthew 24:37-39) During all the time that Noah and his family worked to construct the ark (many decades) Noah preached to the people, only to be ridiculed and ignored. But no one could say that God did not warn them about what he was going to do.....this 'kook' had been rattling on about this 'end of the world' for decades and nothing had happened. No one was taking him seriously, so they did not feel as if anything would eventuate......until it did. But because it was God who closed the door of the ark, no one was able to gain access to the only place of safety.
The inhabitants of Sodom and Gomorrah also felt like their lives would go on without an accounting for their gross immorality, but according to the apostle Peter, these two events "set a pattern" for "ungodly people" of "things to come". (2 Peter 2:5-6)
This is why I believe we need to study the Bible carefully.
When all the positive responders are gathered, it will be like the time God told Noah to enter the ark. The door of opportunity closed back then and it will also today, according to what JW's believe.
We are instructed to keep preaching until the end, giving as many as possible time to 'get on board' so to speak.
Because the message is two fold....it is accomplishing two things.....it is separating the "sheep from the goats" so that when Christ is manifest, both will know that the time has come.
One group will be rejoicing because they have waited so long for the wickedness in this world to end...and now it is coming to pass.
But the other group will be feeling much the same as those who ignored and ridiculed Noah all those thousands of years ago. They saw that everything Noah had told them was the truth, but they did not listen. There were no survivors except the ones on board the ark.
Peter again tells us what the "ark" is for us today....it isn't a vessel made to keep the water out, but a containment within that keeps the world out. It involves water, but in a different way.....it is our baptism, or rather what our baptism symbolizes.....it is our close and personal relationship with God, which like the ark, can take a long time to build. But once it is completed, it becomes the only place of safety.
1 Peter 3:18-21...
"For Christ died once for all time for sins, a righteous person for unrighteous ones, in order to lead you to God. He was put to death in the flesh but made alive in the spirit. 19 And in this state he went and preached to the spirits in prison, 20 who had formerly been disobedient when God was patiently waiting in Noah’s day, while the ark was being constructed, in which a few people, that is, eight souls, were carried safely through the water.
21 Baptism, which corresponds to this, is also now saving you (not by the removing of the filth of the flesh, but by the request to God for a good conscience), through the resurrection of Jesus Christ."
It is not the act of baptism that saves a person, but what the baptism symbolizes, (a death and resurrection) going under the water as one person and being raised up another.....fully dedicated to God to do his will first in all aspects of life. Jesus set the pattern in his own baptism.
That is how I would explain the situation....
