21. Here the received text has: τοῦτο δὲ τὸ γένος οὐκ ἐκπορεύεται εἰ μὴ ἐν προσευχῇ καὶ νηστείᾳ. The words are undisputed in the parallel passage, Mar 9:29, with the exception of καὶ νηστείᾳ omitted by Tischendorf without decisive evidence. Here the omission is supported by אB* 33 and some important versions.