Mark 9:29 New English Translation

²⁹He told them, “This kind can come out only by prayer.”^[a]

Mark 9:29 tc Most witnesses, even early and excellent ones (P^45vid א² A C D L W Θ Ψ ƒ^1,13 33 M lat co), have “and fasting” (καὶ νηστείᾳ, kai nēsteia) after “prayer” here. But this seems to be a motivated reading, due to the early church’s emphasis on fasting (TCGNT 85; cf., e.g., 2 Clem. 16:4; Pol. Phil 7:2; Did. 1:3; 7:4). That the most significant witnesses (א* B), as well as a few others (0274 k), lack καὶ νηστείᾳ, when a good reason for the omission is difficult to find, argues strongly for the shorter reading.

New English Translation (NET)