We have seen that before the plagues are poured out onto the earth, the temple of heaven ceases to function (Rev. 15:5-8). The glory of God is so intense that the seven bowl angels leave the temple, never to return. The closing up of the temple in heaven suggests the end of human probation. From now on there will be no more conversions. Sinners will no longer come to Christ, and saints will no longer fall away from God. So the sufferings experienced in the seven last plagues are not designed to bring anyone to repentance.
What is the point of the plagues, then? If they take place after the close of probation, why add to the world's suffering? If people can no longer repent, it seems vengeful and capricious to torment them further. But the answer may lie in the major underlying theme. God is just when He executes judgment on the wicked, because they are receiving in kind what they have done to others (Rev. 16:5-7). In other words, the punishment fits the crime.
"Is God's judgment always perfectly accurate?" some might ask. "Wouldn't the wicked change if they knew God better or had the same kind of opportunities as the righteous?" The plagues will answer such questions. They show that the wicked will continue to oppose God no matter the circumstances. The worse things get, the more they resist Him. Earlier plagues had brought people to repentance, but now the wicked refuse to return to Him, regardless of what He puts in their path (Rev. 16:9, 11, 21).
The righteous also suffer many things in the last days (Rev. 13:9, 10; 17: 14). But these sufferings do not turn them away from their course either. They remain righteous, and the wicked stay wicked (Rev. 22:11). The close of probation is not an arbitrary decree on God's part. It is simply a time when world affairs reach the point that everyone makes a settled decision for or against Him at the very same time.
The plagues also are not arbitrary, even though they come after the close of probation, because they also serve God's purposes. The turning of the rivers and springs to blood corresponds in a natural way to the crime that is in view. Those who have shed the blood of saints and prophets receive blood to drink as a just reward.
Lord, whenever I am tempted to put immediate pleasure ahead of Your will, keep me mindful of the horrible consequences of sin.