Dein Glück ist heute gutgelaunt, / Doch fürchte seinen Unterstand. - Friedrich Schiller

His Armies, weakened by defeat and defeat, dispirited by misfortune, had unlearned - under beaten generals - that warlike impetuosity which as it is the consequence, so it is the guarentee of success.

Let not thy heart cling to the things which for so short a time deck out thy life. Let him who has, learn to lose, and him who is happy, familiarise himself with what may give pain.

Mit der Dummheit kämpfen die Götter selbst vergebens.
English: Against stupidity the Gods themselves contend in vain.