This appears to be a paraphrasing of:
That soul, I say, herself invisible, departs to the invisible world to the divine and immortal and rational: thither arriving, she lives in bliss and is released from the error and folly of men, their fears and wild passions and all other human ills, and forever dwells, as they say of the initiated, in company with the gods.
~Plato: Phaedo, (360 B.C.)
Phaedo's Socrates divides the dead into three groups, based on the content of their thoughts during life:
The souls of true philosophers pursue their abstract thoughts after death, and these thoughts are purified in a way that is not possible on earth so that finally the philosophers can think the truth.
Souls of the better sort of non-philosophical people, who are moderate in their appetites and just in their social dealings with others, can't join the contemplative circle of philosophers in eternal bliss, because they haven't desired to do so. They are reborn as social, disciplined creatures once again, such as bees, ants or perhaps decent, respectable citizens in human communities, because this is what they have envisioned for themselves. But other people--the unwise souls--are reincarnated as foolish or vicious animals because they simply can't imagine life without the body. Their preoccupations with food and drink, sex, money, fashion, power, enemies and other such external matters lead them back into lives as wolves, donkeys, hawks, kites, and other animals whose consciousness is fully absorbed in material concerns.