J. B. Lightfoot on Colossians 4:2-6

αὐτό, ὡς δεῖ με λαλῆσαι. ^5ἐν σοφίᾳ περιπατεῖτε πρὸς τοὺς ἔξω, τὸν καιρὸν ἐξαγοραζόμενοι· ^6ὁ λόγος 5. ἐν σοφίᾳ] Matt. x. 16 γίνεσθε οὖν φρόνιμοι ὡς οἱ ὄφεις. τοὺς ἔξω] ‘_those without the pale_’ of the Church, the unbelievers; as in 1 Cor. v. 12, 13, 1 Thess. iv. 12. So οἱ ἔξωθεν, 1 Tim. iii. 7. The believers on the other hand are οἱ ἔσω, 1 Cor. v. 12. This mode of speaking was derived from the Jews, who called the heathen החיצונים (Schöttgen on 1 Cor. _l.c._), translated οἱ ἐκτός Ecclus. Prol. and οἱ ἔξωθεν Joseph. _Ant._ xv. 9. 2. ἐξαγοραζόμενοι κ.τ.λ. ‘_buying up the opportunity for yourselves_, letting no opportunity slip you, of saying and doing what may further the cause of God’: comp. Ephes. v. 16. The expression occurs also in Dan. ii. 8 οἶδα ὅτι καιρὸν ὑμεῖς ἐξαγοράζετε, i.e. ‘are eager to gain time’. Somewhat similar are the phrases τὸν χρόνον κερδαίνειν, τὸ παρὸν κερδαίνειν. In much the same sense Ignatius says, _Polyc._ 3 τοὺς καιρὸυς καταμάνθανε. For this sense of ἐξαγοράζω ‘coemo’ (closely allied in meaning to συναγοράζω), see Polyb. iii. 42. 2 ἐξηγόρασε παρ’ αὐτῶν τά τε μονόξυλα πλοῖα πάντα κ.τ.λ., Plut. _Vit. Crass._ 2. More commonly the word signifies ‘to redeem’ (see the note on Gal. iii. 13), and some would assign this sense to it here; but no appropriate meaning is thus obtained. In Mart. _Polyc._ 2 διὰ μιᾶς ὥρας τὴν αἴωνιον κόλασιν ἐξαγοραζόμενοι it means ‘buying off’, a sense in which ἐξωνεῖσθαι occurs several times. The reason for the injunction is added in Ephes. v. 16, ὅτι αἱ ἡμέραι πονηραί εἰσιν: the prevailing evil of the times makes the opportunities for good more precious. 6. ἐν χάριτι] ‘_with grace, favour_’, i.e. ‘acceptableness’, ‘pleasingness’; comp. Eccles. x. 12 λόγοι στόματος σοφοῦ χάρις, Ps. xliv (xlv). 3 ἐξεχύθη χάρις ἐν χέιλεσί σου, Eccles. xxi. 16 ἐπὶ χέιλους συνετοῦ ἑυρεθήσεται χάρις. In classical writers χάρις λόγων is a still more common connexion; e.g. Demosth. _c. Phil._ i. 38, Dionys. Hal. _de Lys._ §§ 10, 11, Plut. _Vit. Mar._ 44.