After Macbeth murders King Duncan he agonizes over something. What is it?
Macbeth agonizes over the fact that he is unable to say "Amen," when one of the sleeping groomsmen had said "God bless us" just after Macbeth murdered the king. These men are asleep, and it does not seem that they actually knew Duncan was murdered. But Macbeth wonders:...wherefore could not I pronounce “Amen”?
I had most need of blessing, and “Amen”
Stuck in my throat. It is clear that Macbeth is stricken with guilt at the murder of Duncan, and that this is what really bothers him. He is so guilty that he is unable to voice a prayer to God. His wife, still at the point where she has to push him toward carrying out the evil deeds necessary to gain and keep power, tells him to "consider it not so deeply," and that thoughts like these will surely drive him mad. But Macbeth persists, saying that he heard a voice saying that "Macbeth doth murder sleep!" Macbeth, who needed to be encouraged to carry out the murder in the first place, is overcome with guilt.