God's Call to Come Out Of Babylon:
And I heard another voice from heaven, saying,
Come out of her, My people, that ye be not partakers of her sins, and that ye receive not of her plagues. Revelation 18:4
Babylon's Call to Come Into Babylon:
"Furthermore, in this one Church of Christ no man can be
or remain who does not accept, recognize and obey the authority and
supremacy of Peter and his legitimate successors. 
Did not the ancestors
of those who are now entangled in the errors of Photius and the
reformers, obey the Bishop of Rome, the chief shepherd of souls? Alas
their children left the home of their fathers, but it did not fall to
the ground and perish for ever, for it was supported by God.
Let them
therefore return to their common Father, who, forgetting the insults
previously heaped on the Apostolic See, will receive them in the most
loving fashion. For if, as they continually state, they long to be
united with Us and ours, why do they not hasten to enter the Church,
"the Mother and mistress of all Christ's faithful"?
Let them hear
Lactantius crying out: "The Catholic Church is alone 
in keeping the true
worship. This is the fount of truth, this the house of Faith, this the
temple of God: if any man enter not here, or if any man go forth from
it, he is a stranger to the hope of life and salvation. Let none delude
himself with obstinate wrangling. For life and salvation are here
concerned, which will be lost and entirely destroyed, unless their
interests are carefully and assiduously kept in mind." Pope Pius XI 1928
