It is topical at Christmas and Easter though, and preaching to the choir, while vital, is not the highest priority. Church services are wonderful for worship, repentance, supplication, thanksgiving and edification (though none of those things are rightly confined to services either,) but preaching the gospel only to those who already know and accept it quickly reaches marginal returns. There is, after all, a reason Jesus sent out many missionary disciples; the Great Commission is aptly named. A consistent example remains the best witness, hence the invocation of Romans 12:1, but Romans 10:14 and I Peter 3:15 remain valid also. Obviously the latter does not mean randomly brining up the gospel and randomly ramming it down a strangers throat, but there again we come back to "it is topical at Christmas and Easter."