Having addressed each of the household relationships (3:18-4:1), Paul now turns his attention back to the whole church. He gives his final exhortations.
Prayer (2): We devote ourselves to prayer and maintain spiritual alertness in it. The former is what Christ called for (Lk. 11:5-9; 18:1) and exemplified (Lk. 5:16; Mk. 1:35), and the first church practiced it (Acts 2:42)! The latter shows that our spiritual vigilance is tied to prayer. Without prayer you're sure to be spiritually drowsy![1] Christ won for us on the cross an open access to the holy God (Heb. 10:19). With thanks[2] we draw near to Him and stay alert!
Evangelism (3-6): One key topic for prayer is evangelism. Divine intervention is indispensable for the spread of the gospel. Hence, even the Apostle asked for prayer. God alone can open a door for the Word. He alone can enable a person to make Christ known.[3] Also, the church at large can reach unbelievers ("outsiders"). Our everyday contact with them is an opportunity![4] We leverage it and "walk with wisdom,"[5] esp., in terms of what we talk about. A wise walk means a wise talk, full of spiritual flavor, always speaking of God's grace.[6] The right response to an outsider is much easier when we're ready[7] with grace.
[1] Time with the holy God in prayer keeps us spiritually alert. The Lord gave the disciples a similar twofold command at Gethsemane: "Keep watching [same Greek verb as Col. 4:2] and praying" (Matt. 26:39-41).
[2] Thanksgiving is to ever attend our prayers. It is the mode of prayer as it was the mode of life in 3:15-17.
[3] NASB's "make it clear" is better rendered as "make it known [pha-ne-ro-ō (φανερόω)]" (NET). The gospel is veiled/incomprehensible to the unbelieving (2 Cor. 4:3-4) until God opens their eyes (Acts 16:14; 26:17-18).
[4] "Making the most of" is ex-a-go-ra-zō (ἐξαγοράζω) which means to buy out something. Like shoppers on Black Friday, we aggressively take advantage of the opportunity that God gives us to proclaim Christ.
[5] "Conduct yourselves with wisdom" is literally "walk with wisdom." This is a wise walk before outsiders.
[6] "Seasoned with salt" means flavor. It parallels "with grace [God's grace]." Grace is the flavor in our message.
[7] "Seasoned" is a perfect participle which shows seasoning is done and ready. This speaks of preparedness.