Spurgeon anecdote

I was looking for something just now and I came across this Spurgeon anecdote from W Y Fullerton's biography (see here). What days they were when Spurgeon was young.

A story about his grandfather conveys an idea of his attachment to the Gospel and his unconventional methods in declaring it, better than pages of description, and suggests that his grandson had caught his spirit. C H Spurgeon had been announced to preach at Haverhill in Suffolk, and - an exceptional incident - he was late in arriving. So his grandfather began the service and, when the expected preacher did not arrive, proceeded with the sermon. The text was "By grace ye are saved." He had gotten some way into his discourse when some unrest at the door made him aware that his distinguished grandson had arrived. "Here comes my grandson," he exclaimed. "He can preach the Gospel better than I can, but you cannot preach a better Gospel, can you, Charles?" Still pressing up the aisle, his grandson replied, "You can preach better than I can. Please go on." His grandfather refused, but he told him the text, explained that he had already shown the people the source and fountainhead of salvation "grace"—and was now speaking of the channel of it "through faith." The younger preacher took up the theme and advanced to the next point—"but not of yourselves"—and was setting forth the weakness and inability of human nature when his grandfather interrupted, and said, "I know most about that." So for five minutes he discoursed, and then his grandson continued again, having his grandfather's whispered commendation "Good! Good!" as he warmed to his subject, until at some special point the old man ejaculated, "Tell them that again, Charles." Ever after, when Charles recalled the text, there came to him with recurring force the words, "Tell them that again."