The Six Books of Proclus on the Theology of Plato, Volume 2

For if every soul is essentially eternal, and by its very being primarily animates some particular body, [it will always animate this body. For the essence of every soul is immutable]. But if this be the case, that which is animated by it is always animated, and always participates of life. That, however, which always lives, by a much greater priority always exists. But that which always is, is perpetual. Hence, that which is primarily suspended from every soul, is perpetual. But indeed every participable soul is primarily participated by a certain body, since it is participable and not imparticipable, and animates its participant by its very being. Every participated soul, therefore, uses a body which is primarily perpetual, and essentially unbegotten and incorruptible.