Flesh is not always appearing dirty based on the kind of personality or shape a soul has it can conform just to blend in but with the constant intent of spotting your garment or leavening your bread to make your service(life) unacceptable before the lord. You can really love to give to a point where you lose the weight of the service of giving but you now secretly permit flesh to create a cubicle of pleasure from it, you enjoy the thank you's  and the honour and preferences it brings to you stealing the aroma it is supposed to send to God,though you have given but you have stolen back the real content of what you gave(Mathew 6:1) ... We must learn to give substances and not take the praise and pleasure of what we have given,rather we should give as though Jesus sent us,you don't take glory (Corinthians 10:31)for being an errand boy,you return it back to your master(Galatians 5:13). Flesh is a thief and flesh can hide in our spiritual activities.