
“The courage of a soldier is heightened by his knowledge of his profession,”
Scientia enim rei bellicae dimicandi nutrit audaciam: nemo facere metuit quod se bene didicisse confidit.
De Re Militari (also Epitoma Rei Militaris), Book I, "The Selection and Training of New Levies"
Context: The courage of a soldier is heightened by his knowledge of his profession, and he only wants an opportunity to execute what he is convinced he has been perfectly taught. (Book 1)