I've heard sermons or speeches that urges church members to serve or preach, "Don't be a consumer christians", "if everyone preaches to just one other then the exponential growth is remarkable", etc.
Personally, I've never been one to favor such urging. In fact, like how Paul refused Barnabas to bring Mark in Acts 15:38, I consider urging one to serve as blinding veil for us from seeing what God's will and true calling for one is.
Therefore, not only would I not urge, I would have to bear the burden of rebuking those who serve with me without calling. And how do I know one has not such calling? If one asks this question, then that's one of the how's.