Paul now moves toward the conclusion of his letter by focusing on prayer. He encourages the Colossians to pray in general with thanksgiving (2b), and then specifically to pray for "us", i.e. Paul (who according to v. 3 is in prison) and Timothy and the circle of people who were in collaboration together (see 4:7ff). He specifically wants prayer to open doors "for the word" (3b), as he proclaims the mystery of Christ (3c, 4a). In vv. 5-6 he admonishes the Colossians to walk in wisdom toward outsiders (5a) and to speak in a salty grace-filled way answering the questions these outsiders may raise (6). In short, Paul is moving toward the end of his letter with a focus on prayer and evangelism.
Τῇ προσευχῇ προσκαρτερεῖτε,
Continue steadfastly in prayer,
γρηγοροῦντες ἐν αὐτῇ ἐν εὐχαριστίᾳ,
( in that you are being) watchful in it with thanksgiving.
προσευχόμενοι ἅμα καὶ περὶ ἡμῶν,
( specifically ), At the same time, pray also for us,
ἵνα ὁ θεὸς ἀνοίξῃ ἡμῖν θύραν τοῦ λόγου
(here is the content of what to pray) that God may open to us a door for the word,
λαλῆσαι τὸ μυστήριον τοῦ Χριστοῦ, διʼ ὃ καὶ δέδεμαι,
( in order that we might) declare the mystery of Christ, on account of which I am in prison—
ἵνα φανερώσω αὐτὸ
( more specifically pray) that I may proclaim it (the mystery of Christ)
ὡς δεῖ με λαλῆσαι.
as it is necessary for me to speak.
Ἐν σοφίᾳ περιπατεῖτε πρὸς τοὺς ἔξω
( Furthermore ) Walk in wisdom toward outsiders,
τὸν καιρὸν ἐξαγοραζόμενοι.
in that you are redeeming the time (i.e. making the best use of the time)
ὁ λόγος ὑμῶν πάντοτε ἐν χάριτι,
( Specifically ) Let your speech always be gracious,
( in that it has been) seasoned with salt,
εἰδέναι πῶς δεῖ ὑμᾶς ἑνὶ ἑκάστῳ ἀποκρίνεσθαι.
in order that you may know how you ought to answer each person.