thank you, macbeth

I was wondering for a while where the phrase "call [ . . . ] power to account" but I couldn't figure out where. Now I know, it was said by Lady Macbeth during her "Out, out, damned spot!" period.

Out, damned spot; out, I say. One, two,—why, then ’tis time to do’t. Hell is murky. Fie, my lord, fie, a soldier and afeard? What need we fear who knows it when none can call our power to account? Yet who would have thought the old man to have had so much blood in him?

SparkNotes