God gives us our faith and He increases it. By this faith we could move a tree far from it's nest but, in the end we had only done as He commanded. Where of then can we boast or take leave of duty. We are yet unprofitable servants. "Prosperity" and "God Within" teachers should be ware. Paul later combines this type teaching, faith as to move mountains but having not love for one another as being futile.
In the midst of the reality going on all around him, Stephen is shown the reality of what is truly going on above. He will not suffer what is to come alone.