A condition that is contrary to fact is false. It is not met. or contrary to fact. People sometimes talk about conditions and what would happen as a result of those conditions being met, but they know that these conditions are not met, so the results also do not happen. (The conditions are the phrase that start with "if.")
In the sentences below, the first clause with "if" is a condition that is contrary to fact. The second clause tells what the result would be if the condition were met. But since the condition is not met, the expected result does not happen.
>"Woe to you, Chorazin! Woe to you, Bethsaida! <u>If the mighty deeds had been done in Tyre and Sidon which were done in you, they would have repented long ago in sackcloth and ashes.</u>" (Matthew 11:21 ULB)
Here in Matthew 11:21 Jesus said that if the people living in the ancient cities of Tyre and Sidon had been able to see the miracles that he performed, they would have repented long ago. The people of Tyre and Sidon did not actually see his miracles and repent. He said this to rebuke the people of Chorazin and Bethsaida who had seen his miracles yet did not repent.
>...if I did not honor the presence of Jehoshaphat king of Judah, I would not pay any attention to you, or even look at you. (2 Kings 3:14 ULB)
Elisha said this to tell the king of Israel that he did not respect him. It was only because Elisha honored the king of Judah that he would pay attention to the king of Israel.
Jesus was talking about a future time when very bad things would happen. He told what would happen if those days of trouble were to last a long time. He did this to show how bad those days will be - so bad that if they lasted a long time, no one would be saved. But then he clarified that God will shorten those days of trouble, so that the elect (those he has chosen) will be saved.
>The Israelites said to them, "<u>If only we had died by Yahweh's hand in the land of Egypt when we were sitting by the pots of meat and were eating bread to the full.</u> For you have brought us out into this wilderness to kill our whole community with hunger." (Exodus 16:3 ULB)
Here the Israelites were afraid they would have to suffer and die of hunger in the wilderness, and so they wished that they had stayed in Egypt and died there with full stomachs. They were complaining, expressing regret that this had not happened.