Tertullian

“ All waters, therefore, in virtue of the pristine privilege of their origin, do, after invocation of God, attain the sacramental power of sanctification; for the Spirit immediately supervenes from the heavens, and rests over the waters, sanctifying them from Himself; and being thus sanctified, they imbibe at the same time the power of sanctifying. Albeit the similitude may be admitted to be suitable to the simple act; that, since we are defiled by sins, as it were by dirt, we should be washed from those stains in waters. ”

“ But a holy thing, of course, hovered over a holy; or else, from that which hovered over that which was hovered over borrowed a holiness, since it is necessary that in every case an underlying material substance should catch the quality of that which overhangs it, most of all a corporeal of a spiritual, adapted (as the spiritual is) through the subtleness of its substance, both for penetrating and insinuating. ”