The Epistle of Mathetes to Diognetus

The anonymous author (traditionally called "Mathetes," simply Greek for μαθητής, "disciple") addresses a question that troubled early Christians: why did God wait so long to send Christ? His answer reveals a sophisticated understanding of salvation history as divine pedagogy. The logic is not that God was indifferent to human sin during "the former time," but that He was allowing humanity to learn something essential through experience: the impossibility of self-salvation.

This passage contains one of the earliest and most striking articulations of soteriological "exchange" in Christian literature, culminating in the famous exclamation "O sweet exchange!" (ὦ τῆς γλυκείας ἀνταλλαγῆς).

Protestant readers have sometimes seen here an early witness to forensic imputation—Christ's righteousness credited to our legal account while our sins are credited to His. However, the language and logic of the passage, read within its original context and the broader patristic tradition, suggest something more participatory and transformative.

The series of exchanges—"the holy One for transgressors, the blameless One for the wicked, the righteous One for the unrighteous, the incorruptible One for the corruptible, the immortal One for them that are mortal"—moves beyond juridical categories. "Incorruptible for corruptible" and "immortal for mortal" are not legal statuses but ontological conditions. One cannot impute incorruption or immortality; these must be genuinely communicated.

The question "what other thing was capable of covering our sins than His righteousness?" uses the language of covering (καλύψαι), which echoes Psalm 32:1 (quoted by Paul in Romans 4:7). Yet the next clause speaks of being justified (δικαιωθῆναι), and the climax speaks of righteousness that "justifies many transgressors." In patristic usage, as Chrysostom later articulates, δικαιόω means "to make righteous," not merely "to declare righteous."

The very next chapter (X) reveals the purpose of this exchange: "And when you have attained this knowledge, with what joy do you think you will be filled? Or how will you love Him who first so loved you? And if you love Him, you will be an imitator of His kindness." The "sweet exchange" leads not to passive enjoyment of an imputed status but to active transformation into imitators of divine kindness.

The verb translated "imparted" (ἐνέπνευσεν, from ἐμπνέω) literally means "breathed into," echoing Genesis 2:7 where God breathed (ἐνεφύσησεν) into Adam the breath of life. The author's point is that the capacity to look upward to God—to know and commune with Him—is not a natural human achievement but a divine gift communicated to humanity at creation. This language of divine impartation is significant for later debates about grace. What God gives is not merely external assistance but something truly bestowed and indwelling. The same logic applies to salvation: just as the original capacity for communion with God was imparted (not merely imputed or declared), so the restored capacity in Christ involves real communication of divine life. As Athanasius would later write: "He became man that we might become god" (On the Incarnation 54)—not by legal declaration but by genuine participation in what God imparts.

Here the author reveals the telos of the "sweet exchange" described in chapter 9. The exchange is not an end in itself—a transaction completed and finished—but the beginning of a transformed life. Having received God's love, we love Him in return; loving Him, we become "imitators of His kindness."

The author's pastoral vision is striking in its practicality: we imitate God not through power, wealth, or dominion, but by bearing one another's burdens, sharing what we have received, becoming "a god to those who receive." This echoes Christ's own self-emptying (Philippians 2:6-8)—He who was rich became poor for our sake. The one who has received the sweet exchange now becomes an agent of that same exchange for others.

This is the liturgical and ascetical logic of Orthodoxy: we receive in order to give; we are filled in order to pour out. Salvation is not a private transaction securing individual heavenly destiny but incorporation into God's own pattern of self-giving love. As Palamas would later summarize: "God does not save us without us" (Homily 33)—and neither does He save others without our participation in His saving work.

The author describes the transformed vision that follows genuine knowledge of God—not merely intellectual assent but a reordering of perception itself. What the world calls life, the Christian sees as death; what the world calls death, the Christian recognizes as the gate to true life. The martyrs who "suffer punishment because they will not deny God" become objects not of pity but of admiration, even envy.

This passage reflects the early Church's lived experience of persecution, but its deeper point is spiritual: salvation involves acquiring new eyes. The "mysteries of God" are not abstract doctrines but a way of seeing reality rightly—heaven ruling over earth, temporal fire as nothing compared to eternal fire, worldly honor as deceit, and the suffering righteous as truly blessed.

This is the patristic understanding of theoria—contemplative vision granted to those being purified and illumined. As one progresses in the life of grace, what once seemed foolishness (the Cross, voluntary suffering, detachment from wealth) becomes self-evident wisdom. The knowledge spoken of here is not information about God but participation in God's own perspective—seeing as He sees, loving what He loves, fearing only what truly merits fear.