St Irenaeus is well known for his proposal that Adam fell from grace because of his immaturity. Like an innocent child, he was unprepared to deal with the seduction and lies of Satan. Though God had prepared for Adam a safe paradise in which to live and though the Word of God walked in the Garden and personally instructed him in goodness and justice, yet “the man was a little one, and his discretion still undeveloped, wherefore also he was easily misled by the deceiver” (AP 12). The Fall was thus virtually inevitable. Today we might say, “he was only human,” but in Irenaeus’ view he was not yet fully human, for he had not yet actualized his capacity for Spirit-filled life.
In light of Adam’s vulnerability to temptation, we might be tempted to blame God for the Fall. Not only must he have known, by his foreknowledge, that Adam would succumb to the words of the Deceiver, but in his wisdom he must have anticipated the likelihood that he would do so. Yet Irenaeus refuses to hold the Creator blameworthy:
If, however, any one say, “What then? Could not God have exhibited man as perfect from beginning?” let him know that, inasmuch as God is indeed always the same and unbegotten as respects Himself, all things are possible to Him. But created things must be inferior to Him who created them, from the very fact of their later origin; for it was not possible for things recently created to have been uncreated. But inasmuch as they are not uncreated, for this very reason do they come short of the perfect. Because, as these things are of later date, so are they infantile; so are they unaccustomed to, and unexercised in, perfect discipline. For as it certainly is in the power of a mother to give strong food to her infant, [but she does not do so], as the child is not yet able to receive more substantial nourishment; so also it was possible for God Himself to have made man perfect from the first, but man could not receive this [perfection], being as yet an infant. …
And on this account does Paul declare to the Corinthians, “I have fed you with milk, not with meat, for hitherto ye were not able to bear it.” That is, ye have indeed learned the advent of our Lord as a man; nevertheless, because of your infirmity, the Spirit of the Father has not as yet rested upon you. “For when envying and strife,” he says, “and dissensions are among you, are ye not carnal, and walk as men?” That is, that the Spirit of the Father was not yet with them, on account of their imperfection and shortcomings of their walk in life. As, therefore, the apostle had the power to give them strong meat — for those upon whom the apostles laid hands received the Holy Spirit, who is the food of life [eternal] — but they were not capable of receiving it, because they had the sentient faculties of the soul still feeble and undisciplined in the practice of things pertaining to God; so, in like manner, God had power at the beginning to grant perfection to man; but as the latter was only recently created, he could not possibly have received it, or even if he had received it, could he have contained it, or containing it, could he have retained it. It was for this reason that the Son of God, although He was perfect, passed through the state of infancy in common with the rest of mankind, partaking of it thus not for His own benefit, but for that of the infantile stage of man’s existence, in order that man might be able to receive Him. There was nothing, therefore, impossible to and deficient in God, [implied in the fact] that man was not an uncreated being; but this merely applied to him who was lately created, [namely] man. (AH 4.38.1-2)
All thing are possible to God, yet it appears that there are some things not even God can unilaterally do—namely, he cannot give any man, not even the first man, the virtues he needs to successfully resist evil and grow in the Spirit. These he must acquire himself through struggle, discipline, and practice. At least I think that is what Irenaeus is suggesting.