πιστὸς ὁ λόγος is a phrase common to all three Pastoral Epistles (1 Tim. i. 15, iii. 1, iv. 9, 2 Tim. ii. 11, Tit. iii. 8; cf. the closely similar ... ἀντεχόμενον τοῦ κατὰ τὺν διδαχὴν πιστοῦ λόγοῦ in Tit. i. 9) and confined to them, though Rev. xix. 9, xxi. 5, xxii. 6 has the analogous οὗτοι οἱ λόγοι πιστοὶ καὶ ἀνηθινοί (εἰσιν).
In 1 Tim. iii. 1 both the connexion and the reading are uncertain. Starting to read at ii. 15 we have ... σωθήσεται δὲ δοὰ τῆς τεκνογονίας ... πιστὸς [v.l. ἀνθρώπινος D* it Ambst.] ὁ λόγος‧ εἴ τις ἐπισκοπῆς 'πρέγεται, καλοῦ ἔργου ἐπιθυμεῖ. Is the 'word' in question that which precedes or that which follows? If it is that which follows, then marcs seems to make nonsense (that volo episcopari is a good wish can scarcely be described as a trustworthy aphorism!), and we are bound to read ἀνθρώπινος – ' they say ...', or ' it is a human, i.e. common saying ...' But may it be that the phrase was intended to refer back to the promise about childbirth, and that it was only a mistaken effort to relate it to what followed that led to the desperate expedient of altering πιστός to ἀνθρώπινος? Hardly; for it would be a very violent and arbitrary alteration; and, besides, ἀνθρώπινος is a v.l. also at 1. Tim. i. 15 (r, Ambst., Aug.), where no such motive could be operative; and the suggestion in W.-H. (notes in loco ) that it is there probably transferred from iii. 1 seems unlikely. But even if we are driven to accept ἀνθρώπινος in 1 Tim. i. 15 also, it is in any case there reinforced by a phrase almost equivalent to πιστός, namely πάσης ἀποδοχῆς ἄξιος.
Thus on any showing we have this latter phrase and at least three firm occurrences of πιστὸς ὁ λόγος besides, and the related phrase in Tit. i. 9, all seeming to point to a certain selective consciousness, as though here maxims (they are mostly soteriological) were being designated as ' sound' and worthy of inclusion, as it were, in a canon of Christian aphorisms. Contrast the λόγος of 2 Thess. ii. 2, which is emphatically not accepted.
There seems to be no cogent reason for treating the phrase as a reader's comment (C. H. Turner's Inaugural Lecture The Study of the New Testament, 1833 and 1920, 1920, p. 21): the γάρ in 2 Tim. ii. 11 hardly carries this weight; it seems to imply rather the author's own knowledge that' some collection of Christian maxims analogous to the' words of Jesus was in process of formation. See W. Lock, I.C.C., on Tit. iii. 8.