That the World Took Its Beginning in Time
7 I know not, indeed, how the heretics, not understanding the meaning of the apostle in these words, consider the term “subjection” degrading as applied to the Son; for if the propriety of the title be called in question, it may easily be ascertained from making a contrary supposition. Because if it be not good to be in subjection, it follows that the opposite will be good, viz., not to be in subjection. Now the language of the apostle, according to their view, appears to indicate by these words, “And when all things shall be subdued unto Him, then shall the Son also Himself be subject unto Him that put all things under Him,” that He, who is not now in subjection to the Father, will become subject to Him when the Father shall have first subdued all things unto Him. But I am astonished how it can be conceived to be the meaning, that He who, while all things are not yet subdued to Him, is not Himself in subjection, should— at a time when all things have been subdued to Him, and when He has become King of all men, and holds sway over all things— be supposed then to be made subject, seeing He was not formerly in subjection; for such do not understand that the subjection of Christ to the Father indicates that our happiness has attained to perfection, and that the work undertaken by Him has been brought to a victorious termination, seeing He has not only purified the power of supreme government over the whole of creation, but presents to the Father the principles of the obedience and subjection of the human race in a corrected and improved condition. If, then, that subjection be held to be good and salutary by which the Son is said to be subject to the Father, it is an extremely rational and logical inference to deduce that the subjection also of enemies, which is said to be made to the Son of God, should be understood as being also salutary and useful; as if, when the Son is said to be subject to the Father, the perfect restoration of the whole of creation is signified, so also, when enemies are said to be subjected to the Son of God, the salvation of the conquered and the restoration of the lost is in that understood to consist.
8. This subjection, however, will be accomplished in certain ways, and after certain training, and at certain times; for it is not to be imagined that the subjection is to be brought about by the pressure of necessity (lest the whole world should then appear to be subdued to God by force), but by word, reason, and doctrine; by a call to a better course of things, by the best systems of training, by the employment also of suitable and appropriate threatenings, which will justly impend over those who despise any care or attention to their salvation and usefulness. In a word, we men also, in training either our slaves or children, restrain them by threats and fear while they are, by reason of their tender age, incapable of using their reason; but when they have begun to understand what is good, and useful, and honourable, the fear of the lash being over, they acquiesce through the suasion of words and reason in all that is good. But how, consistently with the preservation of freedom of will in all rational creatures, each one ought to be regulated, i.e., who they are whom the word of God finds and trains, as if they were already prepared and capable of it; who they are whom it puts off to a later time; who these are from whom it is altogether concealed, and who are so situated as to be far from hearing it; who those, again, are who despise the word of God when made known and preached to them, and who are driven by a kind of correction and chastisement to salvation, and whose conversion is in a certain degree demanded and extorted; who those are to whom certain opportunities of salvation are afforded, so that sometimes, their faith being proved by an answer alone, they have unquestionably obtained salvation; — from what causes or on what occasions these results take place, or what the divine wisdom sees within them, or what movements of their will leads God so to arrange all these things, is known to Him alone, and to His only-begotten Son, through whom all things were created and restored, and to the Holy Spirit, through whom all things are sanctified, who proceeds from the Father, to whom be glory for ever and ever. Amen.
Source: De Principiis (New Advent)