Irenaeus of Lyons · a new plain-English translation from the original language
What is meant by saying that the Father is unknown save to the Son, and by how many means the Son discloses the Father.
For the Lord, showing His disciples that it is He who is the Word producing knowledge of the Father, and rebuking the Jews for imagining they possessed God even while nullifying His Word, through whom God becomes known, declared: The Son is unknown to any but the Father, nor is the Father known to anyone but the Son, and to him to whom the Son chooses to make Him known. So Matthew set it down, and Luke in the same way, and Mark likewise — John alone leaves out this passage. But those eager to appear cleverer than the Apostles render it thus: The Father has been known by none but the Son, nor the Son by any but the Father, and by him to whom the Son chooses to reveal Him — construing it to mean that the genuine God was recognized by nobody prior to our Lord's advent, and claiming that the God announced through the prophets is not Christ's Father. Yet if Christ came into being only when He appeared in human form, and it was merely from Tiberius Caesar's era onward that the Father began to be noted as concerned for mankind — His Word not having accompanied His own creation from the start — then it would hardly have been proper even to announce a different God on that basis, but rather to search out the reasons for such vast neglect and indifference on His part. For no inquiry should be pursued so far, or given such weight, that it alters God Himself and drains away our trust in the Craftsman who sustains us by means of His own handiwork. For exactly as we fix our trust upon the Son, so we must likewise keep a steady and unwavering devotion toward the Father.
And Justin says well, in his treatise directed against Marcion: I myself would not have trusted even the Lord, had He announced a God other than the one who fashioned, shaped, and nourishes us. But because the only-begotten Son proceeded from that single God who both built this world, shaped us, and both sustains and governs everything, summing up in Himself His own handiwork, my trust in Him stands secure, and my devotion toward the Father remains steady, both gifts bestowed upon us by God. For none can come to know the Father save through God's Word — that is, unless the Son discloses Him; nor can anyone come to know the Son except by the Father's favor. And the Son carries out the Father's favor, since the Father dispatches, and the Son is dispatched and arrives. His own Word, moreover, knows the Father, who remains unseen and past our reckoning; and though beyond speech, He Himself makes Him known to us. The Father, in turn, alone knows His own Word. The Lord has shown plainly that matters stand thus on both sides. And it is for this reason that the Son unveils knowledge of the Father through His own showing forth; for knowledge of the Father consists in the showing forth of the Son, since all things come to light through the Word. That we might understand, then, that it is the Son come among us who supplies knowledge of the Father to those who trust Him, He told His disciples: The Son is known to no one but the Father, nor the Father to any but the Son, and those to whom the Son will have disclosed Him — thereby teaching that He Himself is exactly what the Father is, so that we might accept no Father other than the one made known through the Son.
But it is He who fashioned heaven and earth, as His own words demonstrate, and not that counterfeit Father devised by Marcion, or Valentinus, or Basilides, or Carpocrates, or Simon, or the remainder of those wrongly called Gnostics. Not one of these was truly God's son, though Christ Jesus, our Lord, was; and it is against Him that they set their contrary doctrine, presuming to announce a God nobody knows. Yet let them attend to their own words: how can he be unknown, if he is known to them? Anything known even to a handful is no longer unknown. But the Lord never claimed that the Father and Son were wholly beyond knowing — otherwise His coming would serve no purpose. For to what end would He have come at all? Merely to tell us: Seek not after God, for He cannot be found, and you shall not discover Him — as the followers of Valentinus falsely allege Christ said to the Aeons? This is idle talk. Rather, the Lord taught that none can know God save as God instructs him — that God, in other words, is knowable only through God; and that to know Him at all is itself the Father's own will. For those come to know Him to whom the Son will have disclosed Him. And it was for this that the Father disclosed the Son, so that through Him He might become manifest to all, and so that He might welcome into incorruption and unending rest those who trust in Him and live justly; for to trust in Him is to carry out His will. But those who withhold their trust, and thereby shun His light, He will rightly confine within the darkness of their own choosing. To everyone, then, the Father has made Himself manifest, rendering His Word visible to all; and the Word in turn displayed to all both the Father and the Son, since He was beheld by everyone. Hence God's judgment falls justly upon all, who beheld alike yet did not trust alike. For through creation the Word discloses God its Maker; through the world, the Lord who fashioned the world; through the thing formed, the Artisan who shaped it; and through the Son, the Father who begot Him. All these speak the same message to everyone, yet not everyone trusts alike. So too, through the Law and the prophets, the Word proclaimed both Himself and the Father, and the entire people heard the same message, yet not all believed alike. And through the Word rendered visible and tangible, the Father was displayed, though not everyone believed in Him alike; yet everyone beheld the Father within the Son, for the Father remains unseen within the Son, while the Son is the Father's visible likeness. For this reason all, standing in His presence, spoke of Christ and called Him God. Even the demons, upon beholding the Son, cried out: We know who you are, God's Holy One. And the Devil too, testing Him and beholding Him, said: If you are God's Son — everyone indeed beholding and speaking of Son and Father, yet not everyone trusting.
For it was proper that the truth receive attestation from every quarter, and that a judgment follow bringing salvation to those who trust and condemnation to those who withhold trust, so that everyone might be judged fairly, and that the faith directed toward Father and Son might be established by every witness — confirmed, that is, by testimony drawn from all sides: from His own people, since they count as friends, and from outsiders, since they count as foes. For proof is genuine and beyond dispute when it draws separate testimonies even out of one's own opponents — who, persuaded here by the plain witness of their own eyes, both attest and confirm the fact, only afterward lapsing into hostility, laying accusations, and wishing their own admission were untrue. It was not, then, some other being who remained known while another said: The Father is known to none, but one and the same, the Father submitting everything to Him and gathering testimony from every source — that He is genuinely man, and genuinely God — witnessed by the Father, by the Spirit, by the angelic host, from creation itself, from humankind, from the fallen spirits, from demons, from the adversary, and finally from death itself. The Son carries out all the Father's business, start to finish, and apart from Him nobody can come to know God. For the knowledge of the Father consists in the Son; and knowledge of the Son resides in the Father, made known through the Son. It is for this reason the Lord stated: The Son is known to none but the Father, nor the Father to any but the Son, and those to whom the Son will have made Him known. Now will have made known is stated not merely of a future moment, as though the Word only began disclosing the Father once born of Mary, but is set forth as holding true across the entire span of time. For the Son, present alongside His creation since the beginning, discloses the Father to whomever He chooses, whenever He chooses, and in the manner the Father chooses. And it is for this reason that, in every respect and throughout every sphere, there exists a single God, the Father, and a single Word, and a single Son, and a single Spirit, and a single salvation extended to everyone who trusts in Him.