The hair is the very outermost part of the body, and "hair" in the Bible represents the outermost expression of whatever the body represents. In most cases, the hair and beard are discussed in connection with prophets and other holy men. Since they represent the Lord as He is expressed through the Bible, their hair and beards represent the literal, external stories of the Bible -- which is why they were forbidden to shave or clip their hair. In other cases, the hair and beard can represent the external truths a person uses to live, the day-to-day ideas. Very often, the hair and beard are connected with power and strength in the Bible, Samson being the most obvious example. This is because the whole power of the Bible, in all its depth and meaning, is contained within those literal stories we read. If we disregard the stories, then we will cut ourselves off from the power of the Bible, the same way Samson lost his strength when Delilah cut his hair. This is also why calling someone "bald" was considered a great insult, why shaving the heads of captives was a way to humiliate them, and why people would shave their own heads as either a sign of mourning or as a sign of transition a new level of understanding -- removing the old external ideas so new ones can grow in their place. "Hair" can also be used in the negative, to represent the falsities that can guide someone in an evil life.

2577. And with all. That this signifies that so also are the derivative truths, namely, those of memory and of the senses, is evident from what has been said above, and from the series itself; for it is said just above, “behold it shall be unto thee a veiling of the eyes unto all who are with thee;” by which are signified rational truths, which are like a veil to spiritual truths; and it is now said again, “with all;” by which are therefore signified still lower truths which are derived from rational truths; these being no other than what are called memory truths and sensuous truths. That these truths are derived from rational truths is evident from the order of influx. Interior things flow into exterior things; or what is the same, higher things into lower; but not the reverse. It indeed appears otherwise, namely, that man becomes rational by means of the things of sense and of memory, but this is a fallacy. Good from the Lord is constantly flowing in through man’s rational faculty, and it meets and adopts to itself the knowledges in the memory; and insofar as it can do this, and dispose them in due order, so far the man becomes rational. The case herein is the same as with the good and truths which are called those of faith: good from the Lord flows into truths, and adopts them, and insofar as it can do this the man becomes spiritual; although it appears as if truths, called the truths of faith, flow in, and render the man spiritual. It is also owing to this appearance that the truth of faith is so much cultivated at this day, while the good of charity is not thought of.