11 Since therefore, as soon as He so pleased, He did become known not only to the Æons, but also to these men who lived in these latter times; but, as He did not so please to be known from the beginning, He remained unknown— the cause of ignorance is, according to you, the will of the Father. For if He foreknew that these things would in future happen in such a manner, why then did He not guard against the ignorance of these beings before it had obtained a place among them, rather than afterwards, as if under the influence of repentance, deal with it through the production of Christ?
For the knowledge which through Christ He conveyed to all, He might long before have imparted through Logos, who was also the first-begotten of Monogenes. Or if, knowing them beforehand, He willed that these things should happen [as they have done], then the works of ignorance must endure for ever, and never pass away. For the things which have been made in accordance with the will of your Propator must continue along with the will of Him who willed them; or if they pass away, the will of Him also who decreed that they should have a being will pass away along with them.
And why did the Æons find rest and attain perfect knowledge through learning [at last] that the Father is altogether incomprehensible? They might surely have possessed this knowledge before they became involved in passion; for the greatness of the Father did not suffer diminution from the beginning, so that these might know that He was altogether incomprehensible. For if, on account of His infinite greatness, He remained unknown, He ought also on account of His infinite love to have preserved those impassible who were produced by Him, since nothing hindered, and expediency rather required, that they should have known from the beginning that the Father was altogether incomprehensible.
Source: Adversus haereses (New Advent)