The Gospel of the Kingdom is Good News for both Heaven and Earth. This is not an "either-or" proposition, but a "both-and" deal.
Participating in the fullest outworking of the Great Commission [that is, participating in the joy of leading non-believers to a point of conversion, and participating in the on-going process of helping believers to observe all that Christ commanded] is like two legs of a marathon runner.
We must certainly share the Good News that Christ took our sins upon Himself at the cross for the personal salvation of human beings. People must hear that Christ died for their sins in order to believe it (Rom. 10:14).
At the same time, we must be diligent to help those who have received Christ as their personal Savior to fulfill the on-going purpose for which they are saved.
A big part of this on-going purpose involves Christ living out His life through His people in the context of their whole lives, which, for nearly half our waking hours, takes place at work.
We begin our new life in Christ through personal reconcilation to God by His grace, putting our trust in Christ alone to save us. And we continue our earthly role of reconciling all things to Him, including our work things, by means of that same grace.
Apart from Him, we can do nothing to save ourselves. And by the same grace that we exercised for our personal salvation, we are to let our salvation be "worked out" [expressed, or demonstrated] in the world around us, even as we're pounding nails, driving taxis or selling real estate. "...for it is God who is at work in you, both to will and to work for His good pleasure (Phil. 2:12-13)." That's grace in action, and it's a 24-hour deal.
Personal salvation is the critical starting point. It is essential to the Gospel of the Kingdom. But we must also bear in mind that we are not just saved from something. We are saved for something. And that "something" has a lot to do with our everyday work in the world.
We are not saved by good works, but we are saved for good works (Eph. 2:1-10). What better place to live out those works than in the workplace?