Ambrose to Felix, Bishop of Comum, 380 AD:

Aaron indeed once stood in the midst,* interposing himself to prevent death passing over to the hosts of the living from the carcases of the dead. But He, as the Word, ever stands within each of us, although we see Him not, and separates the faculties of our reason from the carcase of our deadly passions and pestilential thoughts

This quote is interesting because it gets to an element of biblical counseling – or soul care: all clinical psychology is trying to change how a person thinks, desires, acts from some undesired state to what is perceived as a better state. Here Ambrose states two things: (1) Christ does change our thinking; (2) our reason has been corrupted by “deadly passions”.

What I cannot tell is whether he holds to an idea that human reason is uncorrupted and it is merely desire which corrupts. Does he hold that all desire or merely “deadly passions” are the culprit.