Thanks for the question. I'll try to give a coherent logical answer. I read into your question a concern that we not adopt the model of social Gospel and Christian philanthropy as a means to favor with and service to God. Synergism.
My thoughts are more along the lines of the two great commandments. Paul later breaks this down to love of neighbor. Love of God must exist for love of neighbor to be extended. How do I love my neighbor? By serving him. How do I serve him? By fullfilling my calling with excellence. In so doing I am giving a cup of water in His name.
Evangelical theology has burdened those in the pew with the law based mandate that they are all to be little street preachers. Everyone they meet being a mark with which to share the gospel.
That's a nice law based idea. "You aren't doing enough witnessing".
That is not the only means and way which God calls his people to serve. The engineer working at Boeing designing air foils is serving his fellow man by designing the best air foil that he can. While he is working I want him thinking air foil rather than how to win the company to Jesus.
As he is there fulfilling his calling he will have ample opportunity to share his faith and the hope that he has in Christ.
I know of an incident which happened last week. A healthcare worker was dealing with a younger woman who was beginning to cycle into episodes of exacerbation of COPD related to heavy smoking. Fulfilling the calling of vocation the healthcare worker gave great care and concern to the woman concerning health. The lady recognized the level of care, something beyond a "you just need to quit smoking" speech. She was immensely thankful. A cup of water was given in Christ's name. The giving of that cup opened the door for the person to speak of hope and share the Gospel.
Each man serves and Glorifies God through the calling he has been given. This is a large part of the good works prepared for him.
There is nothing in the world so damaged that it cannot be repaired by the hand of almighty God.
I encourage you to know this because without this certainty we should all of us be mad.
"Appointment with Death"
By Agatha Christie