Sir Richard C. Jebb, Commentary on Sophocles: Oedipus Tyrannus

[198] τελεῖν γὰρ ... ἔρχεται Reading τελεῖν, as Herm. suggested, instead of τέλει, I construe thus: —εἴ τι νύξ ἀφῇ, ἦμαρ ἐπέρχεται τελεῖν τοῦτο, “If night omit anything （in the work of destruction）, day comes after it to accomplish this.” τελεῖν is the infin. expressing purpose, as often after a verb of going or sending, where the fut. participle might have been used: cp. Hdt. 7.208 “ἔπεμπε ... κατάσκοπον ἱππέα, ἰδέσθαι”[ = ὀψόμενον] ὁκόσοι τέ εἰσι, κ.τ.λ.: Thuc. 6.50 “δέκα δὲ τῶν νεῶν προὔπεμψαν ἐς τὸν μέγαν λιμένα πλεῦσαί τε καὶ κατασκέψασθαι ... καὶ κηρῦξαι.” Here the pres. inf. is right, because the act is not single but repeated. Observe how strongly τελεῖν is supported by the position of the word （“To accomplish, —if night omit aught, —day follows”）. No version of τέλει explains this. The most tolerable is: —“In fulness— if night omit aught—day attacks（ἐπέρχεται） this”: but I do not think that such a rendering can stand. See Appendix.

εἰ ... ἀφῇ Cp. 874 εἰ ὑπερπλησθῇ （lyric）: Soph. OC 1443 “εἰ στερηθῶ” （dialogue）: Soph. Ant. 710 “κεἴ τις ᾖ” （do.）. In using εἰ with subjunct., the Attic poets were influenced by the epic usage, on which see Monro, Homeric Grammar sect. 292. The instances in classical prose are usu. doubtful, but in Thuc. 6.21 “εἰ ξυστῶσιν” has good authority.