Barnabas, Epistle 11.8, 11
See how he set the water and the cross together. For this is what he means: blessed are those who hoped in the cross and went down into the water. This means that we go down into the water loaded with sins and dirt, and we come up bearing fruit in the heart — the fear and the hope that are toward Jesus, held in the Spirit.
Greek
αἰσθάνεσθε, πῶς τὸ ὕδωρ καὶ τὸν σταυρὸν ἐπὶ τὸ αὐτὸ ὥρισεν. τοῦτο γὰρ λέγει: μακάριοι οἳ ἐπὶ τὸν σταυρὸν ἐλπίσαντες κατέβησαν εἰς τὸ ὕδωρ. τοῦτο λέγει ὅτι ἡμεῖς μὲν καταβαίνομεν εἰς τὸ ὕδωρ γέμοντες ἁμαρτιῶν καὶ ῥύπου, καὶ ἀναβαίνομεν καρποφοροῦντες ἐν τῇ καρδίᾳ τὸν φόβον καὶ τὴν ἐλπίδα εἰς τὸν Ἰησοῦν ἐν τῷ πνεύματι ἔχοντες.