The great captain Gabriel Angelos said that, while rushing towards a daemon prince. A great man who had come to understand that sooner or later chaos consumes all, we are fighting a lost war, but as servants of the Emperor we will rather die in battle rather than seeing a world consumed by chaos.
and im just gonna quete Ragnar Blackmane: We may be few, and our enemies many. Yet so long as there remains one of us still fighting, one who still rages in the name of justice and truth, then by the Allfather, the galaxy shall yet know hope. i dont know why there is grey stuff around it
Speh marines generally make fun of guards and look down on them, but we all know who is really doing all the dirty work