But he [Paul] did not say “dwelling as incomprehensible light” but “inaccessible” which is something greater than incomprehensible. Incomprehensible is used when something sought and explored is not grasped by those who seek to know it. Inaccessible, on the other hand, is used when the beginning of the search has not even begun and when someone is not able to do so. A sea is called incomprehensible when divers let themselves down into the great deep but they are unable to find the ocean floor. Something is said to be inaccessible when the beginning cannot be sought or explored.
Ἀλλ’ οὐδὲ φῶς οἰκῶν ἀκατάληπτον εἶπεν, ἀλλὰ ἀπρόσιτον, ὃ τοῦ ἀκαταλήπτου πολλῷ μεῖζόν ἐστι. Τὸ μὲν γὰρ ἀκατάληπτον λέγεται, ὅταν ἐρευνηθὲν καὶ ζητηθὲν μὴ καταληφθῇ παρὰ τῶν ζητούντων αὐτό· ἀπρόσιτον δέ ἐστιν, ὃ μηδὲ ἐρεύνης ἀνέχεται τὴν ἀρχήν, μηδὲ ἐγγὺς αὐτοῦ γενέσθαι τις δύναται. Οἷον ἀκατάληπτον λέγεται πέλαγος, εἰς ὃ καθιέντες ἑαυτοὺς οἱ κολυμβηταὶ καὶ πρὸς πολὺ καταφερόμενοι βάθος, τὸ πέρας ἀδυνατοῦσιν εὑρεῖν· ἀπρόσιτον δὲ ἐκεῖνο λέγεται, ὃ μήτε τὴν ἀρχὴν ζητηθῆναι δυνατόν, μηδὲ ἐρευνηθῆναι.