Macbeth (unnatural) vs. the Witches (supernatural, fate, time): Macbeth wants to know the worst news from the worst sources. He certainly in abusing their prophecies and subverting nature and time in an attempt to retain power.
Macbeth vs. Macduff: the witches prophecies tell him to "Beware Macduff." Later, after Macduff hears of his family's death, vows revenge. This foreshadows the duel in Act V.
Macbeth vs. the Macduffs: Macbeth attempts to kill Macduff and his entire family. Macbeth has now killed innocent women and children.
Lady Macduff vs. Macduff/son: she calls her husband a coward for abandoning them. Macduff, not present, has fled to aid Malcolm in England. Later, after Malcolm tells him he was just testing him, they will have the first (*and only*) honest conversation in the entire play.
Malcolm vs. Macduff: Pretending to be as cruel as Macbeth, Malcolm questions Macduff as to his loyalty to Scotland.