The three weird sisters are preparing to meet Macbeth again.
".. your wife and babes/ Savagely slaughtered.." (4.3.240-241)
"Merciful heaven!" (4.3.244)
The witches summon three apparitions who instruct Macbeth to beware Macduff is still alive and fled to England. This make Macbeth determined to kill Macduff and his family so they wont take away his Crown.
"...Macbeth/ Is ripe shaking, and the power above/ Put on their instruments. Receive what cheer you/ may" (4.3.280-281)
Macbeth sent murderer's to kill Macduff's family. Lady Macduff and her son were murdered. She yells "Murder!" as she tries to escape but fails
Ross tells Macduff his family has been slaughtered by murderers sent by Macbeth. Macduff is shocked and depressed about his families death. Malcolm was there to hear the news and was surprised and felt sorry for Macduff's family's death.
"Fell slaughter on their souls. Heaven rest them now" (4.3.267)
,Macduff is planning to get revenge on Macbeth for killing his family. He is decideing to kill Macbeth and if he escapes may God help him.
"Wthin my sword's length set him. if he 'scape,/ Heaven forgive him too" (4.3.274-275)