[17:21] 1 tc Many important mss (א* B Θ 0281 33 579 892* pc e ff1 sys,c sa) do not include 17:21 “But this kind does not go out except by prayer and fasting.” The verse is included in א2 C D L W Ë1,13 Ï lat, but is almost certainly not original. As B. M. Metzger notes, “Since there is no satisfactory reason why the passage, if originally present in Matthew, should have been omitted in a wide variety of witnesses, and since copyists frequently inserted material derived from another Gospel, it appears that most manuscripts have been assimilated to the parallel in Mk 9.29” (TCGNT 35). The present translation follows NA27 in omitting the verse number as well, a procedure also followed by a number of other modern translations.
[7:8] 2 sn The actions of asking, seeking, and knocking are repeated here from v. 7 with the encouragement that God does respond.
