Matthew 17:21, “this kind goes not out but by prayer and fasting”
Matthew 17:21 is missing from some modern Bibles because reading A ends the answer at Matthew 17:20, while reading B includes the sentence about prayer and fasting. The difference concerns whether that sentence migrated into Matthew or belonged there.
The APB text at this verse
The manuscripts, editions, and versions
The committee record at this verse
The APB's translation committee works blind: it is never told it is translating the Bible, never given a book name or a verse number, and it never sees the witnesses above. Since revision 3.5, the places where the manuscripts disagree are decided before translation by three readers, Grok 4.3, GPT-6 Astra, and Claude Fable 5.1, who see the readings and the witnesses by age and class but never a reference or a manuscript name. Whatever was done at this verse was done on the language and the evidence alone, and the record is public.
Matthew 17:21: set in brackets as a disputed passage, wording kept.
“The base text reads λέγει. The copies also carry Ἰησοῦς [greek majuscule; later majority tradition]; the committee kept the base text. Default wording chosen because the external evidence favors λέγει and the internal evidence supports it as the source of Ἰησοῦς.”
“The base text reads ὀλιγοπιστίαν. The copies also carry the omission [greek majuscule; later majority tradition]; the committee kept the base text. Default wording chosen because the external evidence favors ὀλιγοπιστίαν and internal evidence makes the omission in the omission secondary.”
“The base text reads ἔνθεν. The copies also carry the omission [greek majuscule; later majority tradition]; the committee kept the base text. Default wording chosen; evidence favors ἔνθεν.”
“The base text reads λέγει. The copies also carry Ἰησοῦς εἶπεν [greek majuscule; later majority tradition]; the committee kept the base text. The early and independent support for λέγει outweighs the later and narrower support for Ἰησοῦς εἶπεν, and the internal evidence favors the harder reading.”
“The base text reads ὀλιγοπιστίαν. The copies also carry ἀπιστίαν [greek majuscule; later majority tradition]; the committee kept the base text. Default wording chosen because early independent witnesses favor ὀλιγοπιστίαν and internal evidence supports it as the source of the variant.”
“Included from the Faithlife/SBLGNT apparatus at Matthew 17:20 as a traditional verse addition. Witnesses: Treg, RP.”
The APB 3.5 decision first set Matthew 17:21 in brackets while retaining its wording: “set in brackets as a disputed passage, wording kept.” The committee’s printed text therefore includes the sentence in brackets after Matthew 17:20. Its own record calls the unit “Textual supplement: Matthew 17:21” and says it was included as a traditional verse addition. The audit verdict for the pericope is “clean.”
The argument for each reading
If it migrated from Mark
Reading A ends the answer with the mustard-seed saying in Matthew 17:20. Westcott-Hort supports that ending, and the raw apparatus places the added verse after ὑμῖν under Treg and RP, while WH and NA28 stand without it. The packet characterizes the longer wording as a saying about prayer, with fasting added, that migrates into later manuscripts of Matthew. On this account, the issue is not a different form of the mustard-seed answer, but whether a further sentence entered the Matthean passage through transmission. The wording of reading B remains available for comparison, even where the answer is taken to end at verse 20.
If Matthew wrote it
Reading B prints a complete additional sentence after Matthew 17:20: Τοῦτο δὲ τὸ γένος οὐκ ἐκπορεύεται εἰ μὴ ἐν προσευχῇ καὶ νηστείᾳ. Tregelles prints the verse, and its witness note says that the Byzantine text carries it. The raw apparatus likewise assigns the added verse to Treg and RP. On this account, Matthew’s answer includes both the mustard-seed saying and a statement that this kind does not go out except by prayer and fasting. The packet also identifies the phrase as the church’s proof-text for fasting, which explains why its presence or absence has drawn sustained attention.
The remaining uncertainty is whether the sentence about prayer and fasting belonged in Matthew’s text or entered it during transmission. Its presence adds a statement about fasting; its absence leaves the answer ending with the mustard-seed saying. No doctrine is settled by this one variation. Most doctrines rest on many passages, and the packet presents evidence for both readings without declaring either one original.
Related entries
Witness readings for critical editions are quoted from the SBLGNT apparatus (CC BY 4.0); Hebrew text from the Westminster Leningrad Codex (Open Scriptures Hebrew Bible). Readings of ancient manuscripts and versions are cited as published scholarly fact with their sources linked above. The page does not declare which reading is original.
The registry gives no verdict
The registry does not say which reading is original. Each page lists the witnesses, shows what the committee did with the same text, and leaves the judgment to the reader.