“Man is in the highest degree of materiality, and at the beginning of spirituality; that is to say, he is the end of imperfection and the beginning of perfection. He is at the last degree of darkness, and at the beginning of light; that is why it has been said that the condition of man is the end of the night and the beginning of day, meaning that he is the sum of all the degrees of imperfection, and that he possesses the degrees of perfection. He has the animal side as well as the angelic side; and the aim of an educator is to so train human souls, that their angelic aspect may overcome their animal side. Then, if the divine power in man which is his essential perfection, overcomes the satanic power, which is absolute imperfection, he becomes the most excellent among the creatures; but if the satanic power overcomes the divine power, he becomes the lowest of the creatures. That is why he is the end of imperfection and the beginning of perfection.”
(Abdu’l-Bahia, Baha’i World Faith - Abdu’l-Bahia Section, p. 331-332)