Although the Godly soul is inherent in the Jew and is the ultimate source of his life from the very start, only upon the attainment of the age of maturity (thirteen for a man, twelve for a woman) does it manifest itself in the form of a good inclination, as a drive and desire for attachment to God…
Every spiritual force requires a conduit that is fit for it; for the Godly soul, the requisite vessel is a mature animal soul.
In order for the Godly soul to manifest itself in the life of man in a meaningful way—that is, in a way that enables its refinement and elevation of the animal soul—it requires that an animal soul should be placed in a human body and that it should develop to the point that the godly soul can join it and be revealed through it.
—Rabbi Adin Steinsaltz,