Apologetics is the reasoned defence of our faith. There are many gifted apologists who can argue for the veracity of Christianity and the weakness and falsehood of competing claims. Scholars such as Alister McGrath and William Lane Craig are prominent among them these days.
But we are fooled if we think that simply presenting a rational argument will convince people into faith. Reasoning is important, but it is not the whole story. If you read this 2011 Australian article, you will find evidence that people of all persuasions become more hardened in their attachment to those things which have been falsified.
So what else do we need? Does this not point to the fact that our outreach is a spiritual struggle and requires spiritual resources? We therefore need prayer. Is it not also true that people may be convinced by the signs of a life dedicated to the teaching of Jesus Christ? In that case, we need holiness, too.
Is reason enough for you? What other things are required in our witness?