Act 4- macbeth and witches

In response they summon for him three apparitions: an armed head, a bloody child, and finally a child crowned, with a tree in his hand. These apparitions instruct Macbeth to beware Macduff but reassure him that no man born of woman can harm him and that he will not be overthrown until Birnam Wood moves to Dunsinane. The witches give him these messages that foreshadows the end of his downfall. It is argued that they started his downfall in the first place.