What Book? 1

Early Fantasy and Science Fiction Trivia: 


"Do nothing that can harm your host!" Clement. Context?


"Glad did I live and gladly die

And I laid me down with a will!" Heinlein, quoting R. L. Stevenson. What was Heinlein's context?


"You'll have your chance," he said into the far future. "And by Heaven you'd better make good." Sturgeon, but what story?


"If the stars should appear one night in a thousand years, how would men believe and adore ..." Emerson. The Asimov story?


"Intelligences greater than man's and yet as mortal as his own ..." H. G. Wells. Which book?