Since we have a fallen nature, there is a constant struggle between the flesh and the spirit: the “passions” and our “reason”. Our free will resides, in a sense, between the two. Our reason tells us what we ought to do, while our flesh blindly seeks its own satisfaction.
Most of our sins are a result of us following our passions, rather than our reason which should be guided by the teachings of the faith. Generally speaking, the passions to do not mitigate our culpability. We are culpable to the extent that our free will consents to the disordered desires of the flesh and acts contrary to our reason.
The way passions can mitigate our culpability, is when we act without thought. For example, let’s say someone jumps out from behind a wall and scares you. If you were to “react”, through fear, by saying a bad word, that would probably not be a sin at all, since the action really did not proceed from your will, but of the passion. In other words, you “reacted” so quickly, and without thinking, that your will did not consent to the bad action.
On the other hand, if you became very angry with someone, and then used a bad word, that would be a sin, because the anger caused you to do something wrong. In one case, your passions caused you to react without thought; in the other, your passion resulted in a bad action. Do you see the difference? IT is slight, but in one case, the will is engaged, while in the other you “reacted” without any thought, as you would if you put your hand on a hot oven.
So, generally speaking our passions do not mitigate our sinful actions: they are the cause of them. That is why we must “mortify the deeds of the flesh”. Fasting and self denial helps to strengthen our will so we can resist the inordinate movements of the flesh (passions, emotions, etc.). Self denial is the means to overcome our lower nature. That is why Jesus said: “If thou wilt be my disciple, you must deny yourself, take up your cross, and follow me”.
According to Jesus, the first thing we must do to become His disciple, is to learn to deny ourselves. This self denial strengthens the spirit, and weakens the flesh. Then, according to Jesus, we must learn to embrace our cross - that is, we must learn that the cross is the only way to sanctity, and resolve to actually “embrace” the difficulties that God sends to us. Jesus redeemed the word through the cross, and we are sanctified by embracing our cross.
Suffering is a result of sin. When Jesus redeemed the world, instead of eliminating suffering, He turned a negative into a possitive. He turned the punishement for sin (suffering) into a remedy for sin. When suffering is embraced it acts as a medicine for our soul, crushing sinful tendencies (inordinate desires of the lower nature), and brings a true liberty of the spirit, thus enabling us to follow God (the spirit), rather than our lower nature (the flesh).
So, let us seek to overcome our disordered passions so we can obtain to the true liberty of the saints, and not fall into the error of those today who teach that when we act out of passion, we are not guilty before God. Although the teaching contains a grain of truth, it can be very misleading, since virtually all sin is a result of disordered passions.