What thou wouldst highly,
That wouldst thou holily; wouldst not play false,
And yet wouldst wrongly win.

– William Shakespeare

Macbeth, Act 1, Scene 5. Lady Macbeth says that her husband wants to be king, but wants to achieve it in a “holy” way and not have his hands dirty. In other words he would have no problem being king if Duncan was murdered, so long as he wasn’t part of the murder.