The angel who unites with the third angel is to illuminate the whole earth with his glory. The first angel's message went to every mission station in the world, and in some countries there was the greatest religious interest ever seen since the Reformation. But the last warning of the third angel will exceed these demonstrations of God's power. LF 247.1
The work will be similar to what happened on the Day of Pentecost. God gave the “former rain” at the opening of the gospel to cause the precious seed to spring up. Likewise He will give the “latter rain” at its close to ripen the harvest. (Hosea 6:3; Joel 2:23). The great work of the gospel will not close with less demonstration of God's power than its opening had. The prophecies that were fulfilled with the outpouring of the former rain at the opening of the gospel will be fulfilled again with the latter rain at its close. Here are the “times of refreshing” to which the apostle Peter looked forward (Acts 3:19, 20). LF 247.2
Servants of God, their faces shining with holy devotion, will hurry from place to place to tell the message from heaven. Miracles will take place, the sick will be healed. Satan also works with deceptive miracles, even bringing down fire from heaven (Revelation 13:13). These things will move the inhabitants of the earth to choose sides. LF 247.3
The message will succeed not so much by argument as by the deep conviction of the Spirit of God. The arguments have been presented, publications have exerted their influence, yet Satan has kept many from fully understanding the truth. Now they see the truth in its clearness. Family relationships and church connections are powerless to stop the honest children of God now. Regardless of the forces combined against the truth, a large number take their stand on the Lord's side. LF 247.4