I'm sure that the 144,000 who will recognize Jesus as their Messiah during that time will have a part in preaching the gospel, as well as the two witness who will be prophesying during the first 3 1/2 years of the seven year period. Not to mention all of those who will have heard of the gathering of the church and all of the end-time events that they were told about prior to it happening. I'm sure that there will be a number of people, who after seeing these things coming to pass, will be interested in how they can avoid judgment in the lake of fire. Also, regarding the preaching of the gospel, we have the following that will take place:
"Then I saw another angel flying in midair, and he had the eternal gospel to proclaim to those who live on the earth—to every nation, tribe, language and people. He said in a loud voice, “Fear God and give him glory, because the hour of his judgment has come. Worship him who made the heavens, the earth, the sea and the springs of water.”
"Then I saw another angel flying in midair, and he had the eternal gospel to proclaim to those who live on the earth—to every nation, tribe, language and people. He said in a loud voice, “Fear God and give him glory, because the hour of his judgment has come. Worship him who made the heavens, the earth, the sea and the springs of water.”
1 He cried also in mine ears with a loud voice, saying, Cause them that have charge over the city to draw near, even every man with his destroying weapon in his hand.
2 And, behold, six men came from the way of the higher gate, which lieth toward the north, and every man a slaughter weapon in his hand; and one man among them was clothed with linen, with a writer's inkhorn by his side: and they went in, and stood beside the brasen altar. note note note
3 And the glory of the God of Israel was gone up from the cherub, whereupon he was, to the threshold of the house. And he called to the man clothed with linen, which had the writer's inkhorn by his side;
4 And the LORD said unto him, Go through the midst of the city, through the midst of Jerusalem, and set a mark upon the foreheads of the men that sigh and that cry for all the abominations that be done in the midst thereof. note
5 And to the others he said in mine hearing, Go ye after him through the city, and smite: let not your eye spare, neither have ye pity: note
6 Slay utterly old and young, both maids, and little children, and women: but come not near any man upon whom is the mark; and begin at my sanctuary. Then they began at the ancient men which were before the house.