There is a tension for me in that any social action must intentionally serve the gospel, that is be intended to be an avenue for people to come to saving knowledge of Christ. But I also feel Christians need to do things because they are the right thing to do, not with an ulterior motive of prosyletization. The most promising avenue for me is an articulation of conversion as the work of God, and of social action as a sign of the gospel. But how you consistently and authentically do that in practice I’m not sure.
[This was a comment I originally made on Phil's blog here, but thought it was worthy of a post of its own.]