Melito of Sardis — Fragment on the Incarnation (Reliquiae Sacrae)
For being God and at the same time a perfect human being, the same one confirmed his two substances to us: his deity through the signs in the three years after baptism, and his humanity in the thirty years before baptism — in which, because of the incompleteness according to the flesh, he hid the signs of his deity, though he is true God existing before the ages.
Greek
Θεὸς γὰρ ὢν ὁμοῦ τε καὶ ἄνθρωπος τέλειος ὁ αὐτὸς τὰς δύο αὐτοῦ οὐσίας ἐπιστώσατο ἡμῖν, τὴν μὲν θεότητα αὐτοῦ διὰ τῶν σημείων ἐν τῇ τριετίᾳ τῇ μετὰ τὸ βάπτισμα, τὴν δὲ ἀνθρωπότητα αὐτοῦ ἐν τοῖς τριάκοντα χρόνοις τοῖς πρὸ τοῦ βαπτίσματος, ἐν οἷς διὰ τὸ ἀτελὲς τὸ κατὰ σάρκα ἀπέκρυβε τὰ σημεῖα τῆς αὐτοῦ θεότητος, καίπερ θεὸς ἀληθὴς προαιώνιος ὑπάρχων.