My favorite phrase in another language is: "Dulce et decorum est pro patria mori."
The phrase comes from a poem of the same name by Wilfred Owen. It translates to "It is sweet and fitting to die for ones country." Owen fought, and was killed, in the first world war. He was renowned for his unflinching poems about the waste, futility, carnage, and tragedy of war. The poem, and the final line of Latin quoted here, remind us that when we send off our best and brightest to some far away land to fight our wars, their lives are often cut short in the most grisly manner one can imagine. Owen warns us that we should not
"...tell with such high zest
To children ardent for some desperate glory,
The old lie: Dulce et decorum est
Pro patria Mori."