forewarned is forearmed

Advance awareness of a situation, especially a risky one, prepares one to deal with it.1863, Charles Reade, Hard Cash, ch. 4:[W]hatever a young gentleman of that age says to you, he says to many other ladies; but your experience is not equal to your sense; so profit by mine . . . forewarned is forearmed.1885, G. A. Henty, Saint George for England, ch. 4:Sometimes, they say, it is wiser to remain in ignorance; at other times forewarned is forearmed.circa 1903, Lucy Maud Montgomery, "Why Mr. Cropper Changed His Mind":"Well, Miss Maxwell, I think it only fair to tell you that you may have trouble with those boys when they do come. Forewarned is forearmed, you know."