The Missionaries — D.G. Compton

The spaceship landed on the planet Earth to bring it the message of a new religion and a new way of life that would fit the terrestrial barbarians to take their place in the great community of the Galaxy.

Their motives were beyond reproach. Their objectives were honourable. It was not their fault that humanity distrusted their motives, repudiated their objectives - and did its best to drive the missionaries back into space . . .