1 Macbeth went to see the witches
Macbeth was getting anxious and concerned about what is going on. Thus he wanted to get a better understanding of the situation. This is the reason why he went to see the witches to get a clear picture of what is happening to him.
2 Macbeth was told he couldn't be harmed
Macbeth was told that he could not get harmed by any man who is born from a woman. Also, he was told that he would not be defeated until the time Birnam wood marched towards him. You can see this scene clearly in the Summary of Act 4 and scene 1.
3 Macbeth was warned of Macduff
The witches warned Macbeth about Macduff. When he got to know about Macduff, he planned to kill him. He knew that Macduff has fled to England.
4 Macduff’s family was killed
Macbeth’s men killed the entire family of Macduff. It was tough to see his wife and son being killed. This was shown in the Summary of Act 4- Scene 2. (See Summary of Macbeth Act 4)
5 Malcolm and Macduff decided to fight Macbeth
Both Malcolm and Macduff agreed that fighting Macbeth is the right thing to do.
6 Macduff knew about his family
Macduff already got the information that Macduff was the one who killed his family. This was shown in the Summary of Act 4- Scene 3. (See Summary of Macbeth Act 4 – Scene 3)
7 Macduff wanted revenge
Macduff was angry as he knew that Macbeth killed his family, so he wanted to take revenge from him by killing him. Malcom told Macduff to put his grief into action, and then both of them decided to kill him.