No one should say: I stand firmly upon the foundation of the ancient teachings, and these suffice for me … What do I care for those who doubt! — No opinion can be more selfish or un-Christian that this! It is still possible today for a certain number of men to live upon the foundation of old religions, but in a not too distant future this will no longer be possible. Those who have an insight into that which great social upheavals throw up to the surface, cannot judge in this way. They will realise that it is not possible to quarrel over the fact that theosophy must be proclaimed.
Thinking men know that spiritual science exists in order to supply an answer to the most burning questions, and that it is actually able to reply to all these questions. After all, one can prove or disprove anything, but this is not the essential point: It is impossible to quarrel over a REMEDY; the essential point is the success which we achieve with it. It is exactly the same with spiritual science. Humanity needs spirituality as a remedy, and it can only recover from its illnesses if this remedy streams into it. It is an evolutionary factor of our civilisation, and a giver of life.
Source: Rudolf Steiner – GA 100 – Theosophy and Rosicrucianism: Lecture I – Kassel, 16th June 1907