For they considered not [the miracle] of the loaves: for their heart was hardened.
Berean Study Bible (BSB) - Mark 6:52 >for they had not understood about the loaves, but their hearts had been hardened.
Textus Receptus (TR) - Mark 6:52 >Οὐ γὰρ συνῆκαν ἐπὶ τοῖς ἄρτοις· ἦν γὰρ ἡ καρδία αὐτῶν πεπωρωμένη.