Galatians 5:8

ἡ πεισμονὴ οὐκ ἐκ τοῦ καλοῦντος ὑμᾶς. οὐκ is omitted by D* and some other “western” authorities, e.g. Orig. De Princ. III. i. 7 ἡ πεισμονὴ ἐκ τοῦ καλοῦντος καὶ οὐκ ἐξ ἡμῶν, but evidently read by him in c. Cels. VI. 57.

8. ἡ πεισμονὴ[136], “This persuasion.” The word is rare, and in Ignat. Rom. iii., Justin Apol. I. 53.1 its meaning ambiguous. But in Iren. IV. 33. 7 (πίστις ὁλόκληρος καὶ … πεισμονὴ βεβαία) it is plainly passive. So the forms πλησμονή “satiety,” Colossians 2:23; ἐπιλησμονή, James 1:25; φλεγμονή “inflammation,” “passion,” 4Ma 3:17. So probably here “This persuasion that you have.” The article is demonstrative.

[136] Is affixed it means that all the passages are mentioned where the word occurs in the Greek Bible.

οὐκ ἐκ τοῦ καλοῦντος ὑμᾶς, see notes on Textual Criticism. You have been over-persuaded, but this has been due to merely human art (cf. 1 Corinthians 2:4-5); it has not come from Him whose voice you heard at first, Galatians 1:6. Yet καλ. is not quite timeless; it rather suggests the continuous call of the living God. Yet see Milligan on 1 Thessalonians 2:12.