Upon reflection, the concept of the Church having two aspects, both visible and invisible, is becoming further entrenched in my mind.
The fact that the Church has both of these facets is inescapable.
Beyond this, it is so apt.
Beginning at the beginning, in Genesis, and continuing on throughout the OT, we see that God has revealed that he has two people: the people of promise (the remnant), and his set aside people (the Israelite nation). The Law, and the Promise. The seed of the woman, and the seed of the serpent. Jacob, and Esau. The spiritual reality within the physical appearance is a [the?] major theme running through the OT.
When we get to the NT, Jesus and the Apostles go on to explain and dogmatize the concept.
God's ways are higher than our ways.
We cannot see into the secret counsel of God.
We cannot judge the state, never mind the future state of men's hearts in relation to God.
The Shepherd knows His sheep, and His sheep hear His voice; but the Church can only know the profession (and conduct) of the sheep, and have to act and react based only on those criterea.