All warfare is based on deception.
The line is paragraph 18 of the first chapter, “Laying Plans”. Giles follows it with a note that the truth of the “pithy and profound saying” will be admitted by every soldier.
If you know the enemy and know yourself, you need not fear the result of a hundred battles.
Hence to fight and conquer in all your battles is not supreme excellence; supreme excellence consists in breaking the enemy’s resistance without fighting.
A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines.
A house divided against itself cannot stand.
The rank is but the guinea’s stamp, / The Man’s the gowd for a’ that.