In the story of the Tower of Babel, God confused the language of the people instead of forgiving their attempt to build a tower to reach heaven. This shows a lack of immediate forgiveness for their pride and disobedience.
Another is the story of Jonah. God forgave the people of Nineveh when they repented, but there were still implications and changes as a result of their earlier sins. Also, in the story of Adam and Eve, they were forgiven in a sense, but were cast out of the Garden of Eden and faced various hardships as punishment.
One such story is when God sent the flood to punish humanity for their wickedness.
One such story is the story of Noah's Ark. God commanded Noah to build the ark to save himself, his family, and pairs of every living creature from the flood.
The Exodus is a very significant event. It's when the Israelites were led out of slavery in Egypt by Moses. Another one is the creation of the world as described in the book of Genesis.
Maybe he doesn't like the way his character is often misinterpreted or distorted in fanfiction. Some fanfictions might take his character in directions that he would find unacceptable or disrespectful.
In fanfiction, a scenario could be that the Cullens exclude Bella from important family decisions. This makes her feel like an outsider and unloved. Or perhaps they try to manipulate her into doing something she doesn't want to do, such as leaving her human friends behind. This would lead to her not forgiving them.
One such story could be the Flood narrative where God decides to wipe out most of humanity due to their wickedness. This could be seen as an instance where mercy wasn't immediately apparent.
One of the main themes is the relationship between God and His people. It shows how God chose the Israelites, made covenants with them, and guided them. Another theme is the concept of sin and redemption. The stories often depict the people's disobedience and God's mercy in forgiving them when they repent.
It could lead to a lot of internal conflict for the man. Maybe he's too stubborn or has some deep-seated reasons for not being able to let go.
In some fanfictions, Harry might not forgive McGonagall because she may have made a decision that Harry feels was a great betrayal. For example, if she sided with the Ministry when they were unjustly treating him. It could also be that she failed to protect him or someone he cared about in a crucial moment within the fanfiction's plot.