Grocott & Ward, comps. Grocott’s Familiar Quotations, 6th ed. 189-?.

Extremes

Thus each extreme to equal danger tends,
Plenty as well as want can separate friends.
Cowley.—The Davideis, Book III. Line 205.

The two extremes appear like man and wife,
Coupled together for the sake of strife.
Churchill.—The Rosciad, Line 1005.