“Yet, without true Christians loving one another, Christ says the world cannot be expected to listen, even when we give proper answers. Let us be careful, indeed, to spend a lifetime studying to give honest answers. For years the orthodox,evangelical church has done this very poorly. So it is well to spend time learning to answer the questions of men who are about us. But after we have done our best to communicate to a lost world, still we must never forget that the final apologetic which Jesus gives is the observable love of true Christians for true Christians.”
– Francis Schaeffer (1912–1984), The Great Evangelical Disaster, p. 164-165
Schaeffer was careful to acknowledge in the pages before this quote the necessity of examining the profession people make for Christ which is why he added the adjective “true” in front of the noun “Christian”. And he was just as careful to guard against the tendency to encourage a non-thinking form of apologetic in the church, the sort that would only support a naive form of observable love as the final apologetic.
What he is making much of here is the type of observable love that can only be done in the presence of true Christians who know their differences but are able because of Christ’ own pattern to consider others better than themselves and to serve them and sacrifice for them out of love.
I believe that this final apologetic is often an absent apologetic. People typically describe apologetics as something the church does outwardly for the sake of truth and polemics as something the church does inwardly for the sake of truth, but I think Schaeffer ingeniously explores their overlap here. Our defense before the world is dependent of how we function on a communal level inwardly.