ἀδελφοποίησις

From LSJ

ἐπ' αὐτὸν ἥκεις τὸν βατῆρα τῆς θύρας → you've come to the crux of the matter, come to the point, hit the nail on the head, you've come to the very threshold of the door, you are come to the very threshold of the door, you've arrived at the truth of the matter

Source

Spanish (DGE)

-εως, ἡ
adopción como hermano fig. de hombres por Cristo, Ath.Al.M.26.280A.

German (Pape)

das zum Bruder Machen, Sp.