It is certain that many of the two opposite parties are deceived; they must be disabused.
Faith embraces many truths which seem contradictory. There is a time to laugh, and a time to weep, etc. Responde, ne respondeas, etc.
The source of this is the union of the two natures in Jesus Christ.
And also the two worlds. The creation of a new heaven and a new earth, a new life, a new death, all things double, and the same names remaining.
And finally, the two natures which are in the righteous man, for they are the two worlds, and a member and image of Jesus Christ. And thus all the names suit them, righteous, sinners; dead though living, living though dead, elect, reprobate, etc.
There are then a great number of truths in faith and in morals, which seem contrary to each other, which yet all subsist together in a wonderful order.
The source of all heresies is the exclusion of some of these truths.
And the source of all the objections made by heretics against us is the ignorance of some of these truths.
And for the most part it happens that, unable to conceive the relation of two opposite truths, and believing that admission of one involves the exclusion of the other, they embrace the one and exclude the other, thinking that we on the other hand.... Now exclusion is the cause of their heresy, and ignorance that we hold the other truth causes their objections.
1st example: Jesus Christ is God and man. The Arians, unable to reconcile these things which they believe incompatible, say that he is man, and so far they are Catholics. But they deny that he is God, and so far they are heretics. They assert that we deny his humanity, and so far they are ignorant