When Hashem blesses us, however, He has the power not only to bless us, but to guard the blessing so that it will stay with us. Thought, Action and Speech. Three worlds that can be blemished. This week's Parsha deals with the Nazir. These three separations correct blemishes in the three worlds of Thought, Action and Speech.
Hair grows from the head, the seat of thought.
Thus, cutting the hair represents correcting imperfections in the sphere of thought. Tumah corresponds to the sphere of action. The principal source of Tumah results from contact with a dead body, for before its passing, the body was the epitome of life and action. Wine represents the function of speech. Secrets are communicated by words.