As promised, I offer you a vignette to consider as we think about the matter of culpability and involuntary sins.
Consider a 2 year old that has missed his daily nap, is hungry, and tired of being out in public. He has a meltdown. He kicks, screams, cries, refuses his mother’s comfort because he wants some object he cannot have. The good parent recognizes the child’s distress, whispers in his ear to comfort him, says “no” firmly to his kicks, and finds something for him to eat and a place to take a nap. Has the child sinned? He surely has demanded something, acted aggressively, maybe even disobeyed by going after the object after his mother said to stop. Yes, he sinned. But was it really voluntary? Well, maybe partly. But don’t we consider the circumstances and the fact that his body is not helping matters. We forgive, we overlook, we understand, we help. We do so because we know his choices are not really voluntary.
Now, we may have another reaction altogether when we see our little boy (fully rested and fed) look us in the eye and try to bite his baby brother after we just told him to stop. We know he has great voluntary control here and is in a power struggle. And we respond with appropriate discipline.
We could easily have considered a vignette of a brain injured man or a panic disordered woman. We respond to individuals based not on whether something is sinful or not but on how much voluntary control we think they have and the circumstances in play (environment, biology, understanding, etc.).
So, our bodies can cause us to sin. In the classic sense, we are guilty whether it is voluntary or not. And yet we, and God himself, varies responses to such sins based on a variety of factors. We do not ascribe innocence to those less culpable but do try to determine levels of responsibility. Thankfully, all of it is covered by the cross.
Here’s one way this might matter. I find many afraid to seek biological aids for what they determine to be spiritual problems (addictions, depression, anxiety, etc.). If we see body and soul together, then both body and soul interventions are working toward the same goal.