I beleive the gospel is like this, Adam sinned and that brought death to the whole human race but was that my fault or your fault? Of course it wasnt. But Jesus paid the price for the sin of the whole world and you or I also had nothing to do with that. The only think we can do is to accept his salvation. This gives us the verdict of not guilty in the last judgement. Good works such as witnessing or anything else are done because we are allready saved not because we are trying to impress God with our works. In fact our best works are like filthy rags as it says in the old testament. Any attempt to save ourselves by our own works are effected by our own selfishness and are an insult to God.
Good works are however important to the christian not because we want to be saved but because we are allready saved and many could learn from the work the witnesses do in their dedication to the time and effort they put into witnessing but they will never be saved by anything they do it has allready been done.
lll