Oh, shame to men! devil with devil damn'd

Firm concord holds, men only disagree

Of creatures rational.

John Milton (1608-1674): Paradise Lost. Book ii. Line 496.

Thy purpose firm is equal to the deed:

Who does the best his circumstance allows

Does well, acts nobly; angels could no more.

Edward Young (1684-1765): Night thoughts. Night ii. Line 90.

Thou sure and firm-set earth,

Hear not my steps, which way they walk, for fear

Thy very stones prate of my whereabout.

William Shakespeare (1564-1616): Macbeth. Act ii. Sc. 1.