My friend Mark Keown has recently published Congregational Evangelism in Philippians: The Centrality of an Appeal for Gospel Proclamation to the Fabric of Philippians (Paternoster Biblical Monographs). Here, Mark is responding to the claim that Paul understood the proactive missionary task as the vocation of a few gifted people (apostles and evangelists, but perhaps others). Although Mark has focussed specifically on Philippians in his response, I believe that Colossians has something to say about this matter. This is clear in studying Colossians 4:2-6. Houlden, followed by Dunn, suggests that mission was the task of the apostle, while the church was meant to pray. I find this an awkward suggestion given that Paul, in this specific pericope, has been speaking of the mission in vss. 2-4, and the speaks directly to the issue of congregational mission (whether corporate or individual) in vss. 5-6. While we must concur that Paul sees the congregation's prayers as intrinsically linked to his mission, we must not therefore assume or deduce that it is only apostles and their co-workers who are required to engage in the mission of God. Even Dunn, pg. 261 notes that "the evangelistic overtones and opportunities implied in 4:5-6 (in ordinary conversations) should not be ignored." In fact, the logic of the verse is compelling: a) Conduct yourseves wisely before outsiders, b) make the most of the time you have, c) let your speech be gracious, d) seasoned with salt (Matt 5:13-16), e) ready to answer anyone who asks. This seems to be a list of instructions building on the previous elements noted. a) Conduct sets the context and either validates or invalidates what they will proclaim. b) Take the opportunities that arise in your daily lives. c) Proclamation should be done in welcoming a charitable manner so as to not offend or insult others, but the gospel should be shared, d) and when the gospel is shared, people will have questions, e) which means followers should be ready to respond! I'm not quite sure in what other context these statements would gain coherence.  Houlden, Paul’s Letters from Prison, pg. 215-216 and Dunn, The Epistles to the Colossians and to Philemon, pg. 261. This is also the position adopted by John Dickson, Mission-Commitment in Ancient Judaism and in the Pauline Communities: The Shape, Extent and Background of Early Christian Mission (Mohr Siebeck, 2003). Incidently, Chapter 3 Heralds and partners of Dickson's book, which deals with this topic, is available online, just follow the link to a PDF.