Chapter 11, Verses 54 and 55 - Sun Tzu

When a warlike prince attacks a powerful state, his generalship shows itself in preventing the concentration of the enemy's forces. He overawes his opponents, and their allies are prevented from joining against him. Hence he does not strive to ally himself with all and sundry, nor does he foster the power of other states. He carries out his own secret designs, keeping his antagonists in awe. Thus he is able to capture their cities and overthrow their kingdoms.
~ from The Art of War, Giles translation ~

Go here to read the introductory post to the verses of The Art of War.