Luke 16

1 Wealthy people today often hire managers to look after their money. There is an implicit trust involved. If a manager is found to be cheating and embezzling, he is usually fired.
2 It appears that the wealthy man is already convinced that the manager is cheating him, but he asks the manager to audit himself and make a report.
3 The manager knew that once word got out about why he was fired, no one would trust him to be a money manager again. This made the manager anxious since this was the only kind of work he was suited for, physically and mentally.
4 The dishonest manager devised a scheme that would guarantee him a means to support himself, even while he was not working. He called in all the wealthy man's debtors and reduced their bills. He could do this because he was still the official manager, and the bill would stand even after he was fired. After he was fired, the manager reasoned that he could then go back to these creditors and live off either blackmail or gratitude money.
6 A measure of oil was about nine gallons.
7 A measure of wheat was about ten bushels.
8 The wealthy man admired the manager's resourcefulness, not the dishonest activity. Ungodly men often find it easy to devise clever and dishonest schemes to advance themselves in a worldly manner. It is more difficult to develop honest means of advancement, but the verse implies that it can be done.
9 The worldly lesson to this parable is that dishonest use of money can lead to financial security. The Jews often equated financial status with spiritual status, but Jesus makes it clear that this is not the case.
10 Trust is often "earned" in small steps. If someone proves to be trustworthy in a small matter, he may later be given bigger responsibilities and bigger rewards. Those who reveal that they cheat in small and unimportant matters will not be trusted to work with significant matters.
11 Our conduct in the physical world is a test of our spiritual character. Whether one is wealthy or poor does not matter. People at every financial level can choose to be honest or dishonest. If someone is untrustworthy in their temporary, worldly matters then they will not be trusted to handle more important and eternal spiritual matters.
20 The poor man obviously suffered a disabling disease that prevented him from working and his skin disease would have made him a social and religious outcast. He had to beg to get the food and money he needed to live on. Begging at the rich man's gate may have been a place where a beggar might expect to find a compassionate soul with some spare change to give.
21 The poor man withered away, desiring even the crumbs that carelessly fell from the overflowing table. The poor man was apparently too week to fend off the dogs (unclean animals) that would lick his oozing sores.

The idea is to contrast the life of excess and ease with misery and disease. The rich man could have afforded some food and medicine for the poor man, but had not.

23 This would have been the shocker for the listeners. The rich were considered specially blessed by God for their righteousness while the poor and diseased were considered miserable sinners getting the just punishment. Here we see that is not the case. The rich man was indeed a sinner and had never repented. His punishment was hell.

It would seem that at least some of this parable is allegorical since it is unlikely that anyone in hell will ever converse with anyone in heaven. However, some of the descriptions of hell (i.e., torment and flames) are supported by other verses.

25 The rich man had been rich in material things, but poor in spiritual matters. In contrast, the poor man had no resources, except for his relationship with God.
26 Hell will be a place where, after the Judgement, no one outside will be able to enter (they wouldn't want to anyway) and no one inside will be able to escape. The important thing to realize is that there is no "purgatory" where escape from punishment is possible. On Judgement Day God will separate those who have a positive relationship with Him from those who do not. His decision will be final, which is why it is so important for people to establish that relationship with Him as soon as they can.
30 God has given the whole world the Bible and preachers, but sadly most people do not listen to them. Some people claim they will believe if they see some miraculous act of God.
31 However, the Bible already contains the recorded accounts of many miracles. To test God by demanding a miracle is not a sincere search for God, but a statement of unbelief.

In a sense of prophesy Jesus tells the listeners that people will refuse to believe the message given by someone who has come back from the dead. Jesus would be the one who came back from the dead to display God's power. It is true that some have believed Him, but most still scoff either at the resurrection or at the teachings of God.