We find again other forms of expression, which it is proper to notice. The union between God and the soul is sometimes described
by them as an "essential" union, and sometimes as a "substantial" union, as if there were a union of essence, substance, or being, in the literal
or physical sense. They mean to express nothing more than the fact of the union of pure love, with the additional idea that
the union is firm and established; not subject to those breaks and inequalities, to that want of continuity and uniformity
of love which characterize inferior degrees of experience.