When Jesus said that it would be more tolerable for Sodom in the day of judgment than for those who rejected the proclamation of the apostles in the days of His instrumental ministry, what did He mean?
First, what do I mean by "His instrumental ministry"? I am using the word instrumental in the sense of indirect action--the use of an instrument rather than personal, direct action. It is a fact of life that God accomplishes very few accomplishments in our world by direct personal intervention. The author of Hebrews says that the angels are "ministering spirits, sent forth to minister for them who shall be heirs of salvation" (1:14). They are God's instrumental agents. In the same way the New Testament teaching of human involvement for ministry assumes that God does through people what He wants to do rather than doing it Himself. So, by angels and men, God does what He seeks to accomplish. God apparently seldom directly intervenes. But that does not mean that His ministry is without authority. Jesus told His disciples that men would be held accountable for their treatment of them as if it were treatment of Him. Angels and men are the instruments of God's instrumental ministry.
Second, what about the issue of Sodom's fate in eternal judgment being better than the fate of those cities which rejected the apostolic witness? Sodom is notorious for its fate under temporal judgment. Fiery destruction is a rather awesome way to die. Most cities and their inhabitants are allowed to be eaten up bit by bit by the moral and physical decay that results from ungodly behavior. The fact that Sodom was rained on from heaven indicates that it got a far harsher temporal reaction from God than the typical ungodly city. Even Nineveh, whose wickedness was so great and whose destruction Jonah rather gleefully announced, was not treated so violently. So, to be told that the inhabitants of Sodom will be better treated in the day of judgment than the cities that rejected the apostolic witness had to have been a rather rude shock to the hearers.
It would have been that shock for two reasons. First, most people think of people who deserved fire from heaven as being exceedingly wicked; and second, most people discount the issue of accountability based upon exposure.
Let's look at that. For the cities to get a greater condemnation than Sodom, their wickedness has to have surpassed that of Sodom. There are a couple of ways that can work. Either wickedness is relative, or accountability is relative, or both. What I mean is that wickedness carries a relative vengeance quotient. Telling a lie that hurts someone will get a certain response under divine justice. Murdering someone will get a greater response. The divine reaction is relative to the degree of seriousness of the evil done. But, someone who tells a lie in deliberate violation of the knowledge of the divine will may well get a greater reaction from God than the murderer whose ignorance of the divine will is so great that he does not know that murder is offensive to God. Thus, judgment is based upon two factors: the clarity of the knowledge the person had; and the seriousness of the evil perpetrated.
The greater the clarity, the worse the consequence of the offense--even if the offense alone carries a smaller quotient of seriousness. Bye the same token, the greater the ignorance, the less the consequence of the offense--even if the offense alone carries a larger quotient of seriousness. Thus, the ignorant murderer might actually get off lighter than the knowledgeable liar. This seems to be the point of Jesus' statement to His disciples. They were involved in making the will of God known. That made their hearers liable to greater consequences for rejection than those who never heard.
What has all this to do with the temperature of Hell? Apparently people are subject to degrees of torment in eternal destruction. The particular assignment in condemnation will be determined by two things: what was done and what was known about the will of God when it was done. What does that have to say about the people who live where the truth of the Gospel can hardly be escaped?