Early Church Fathers Agree: Doctrine Develops
Vincent of Lerins
[54.] But some one will say, perhaps, Shall there, then, be no progress in Christ’s Church? Certainly; all possible progress. For what being is there, so envious of men, so full of hatred to God, who would seek to forbid it? Yet on condition that it be real progress, not alteration of the faith. For progress requires that the subject be enlarged [in] itself, alteration, that it be transformed into something else. The intelligence, then, the knowledge, the wisdom, as well of individuals as of all, as well of one man as of the whole Church, ought, in the course of ages and centuries, to increase and make much and vigorous progress; but yet only in its own kind; that is to say, in the same doctrine, in the same sense, and in the same meaning.
. . . in the case by which I have illustrated it the change is made by successive subtractions; whereas here perfection is reached by additions. For the matter stands thus. The Old Testament proclaimed the Father openly, and the Son more obscurely. The New manifested the Son, and suggested the Deity of the Spirit. Now the Spirit Himself dwells among us, and supplies us with a clearer demonstration of Himself. For it was not safe, when the Godhead of the Father was not yet acknowledged, plainly to proclaim the Son; nor when that of the Son was not yet received to burden us further (if I may use so bold an expression) with the Holy Ghost; lest perhaps people might, like men loaded with food beyond their strength, and presenting eyes as yet too weak to bear it to the sun’s light, risk the loss even of that which was within the reach of their powers; but that by gradual additions, and, as David says, Goings up, and advances and progress from glory to glory,the Light of the Trinity might shine upon the more illuminated. (Fifth Theological Oration: On the Holy Spirit, 26; NPNF2-7)