Unless there is God. If the God of the Bible exists, and there is a True Reality beneath and behind this one, and this life is not the only life, then every good endeavor, even the simplest ones, pursued in response to God’s calling, can matter forever. That is what the Christian faith promises.
From Tim Keller, part 2 of his posts on how the Gospel changes our apologetics...
...a gospel-shaped apologetic starts not with telling people what to believe, but by showing them their real problem. In this case we are showing secular people that they have less warrant for their faith assumptions than we do for ours. We need to show that it takes faith even to doubt.
There is a way of telling the gospel that makes people say, “I don’t believe it’s true, but I wish it were.” You have to get to the beauty of it, and then go back to the reasons for it. Only then, when you show that it takes more faith to doubt it than to believe it; when the things you see out there in the world are better explained by the Christian account of things than the secular account of things; and when they experience a community in which they actually do see Christianity embodied, in healthy Christian lives and solid Christian community, that many will believe.