One cloud is enough to eclipse all the sun. Pr.
One could not commit a greater crime against public interests than to show indulgence to those who violate them. Richelieu.
One could not wish any man to fall into a fault; yet it is often precisely after a fault, or a crime even, that the morality which is in a man first unfolds itself, and what of strength he as a man possesses, now when all else is gone from him. Goethe.
One could take down a book from a shelf ten times more wise and witty than almost any man's conversation. Campbell.
One crime is everything; two, nothing. Mme. Deluzy.
One crow never pulls out another's eyes. 5 Pr.
One crowded hour of glorious life / Is worth an age without a name. Scott.
One does not love the heaven's lightning (seen in a great man) in the way of caresses altogether. Carlyle.
One dog can drive a flock of sheep. Pr.
One doth not know / How much an ill word may empoison liking. Much Ado, iii. 1.