As the Daishonin writes, to share the Mystic Law is to practice just as the Buddha teaches. It is the most difficult of all undertakings. But we gain the same benefit from enabling someone to hear about the correct teaching whether or not they immediately take faith in it. In either case, we are carrying out the supremely noble work of the Buddha.

From The Wisdom for Creating Happiness and Peace, part 2, revised edition, p. 242