Father Abraham - Lincoln and his Sons

[Eva Elisabeth]

Regarding Robert's relationship with his father and v.v., what would you think of this incident?

"In 1859-1860, Mr. Lincoln's eldest son, Robert Todd Lincoln, attended Phillips Exeter Academy while preparing for entry to Harvard College. Robert was asked to read the Declaration of Independence at an Independence Day celebration, but declined to do so without his father's permission. Friend Frank Fuller wrote Robert's father asking for the permission and claimed to have received a reply from Springfield: 'Tell Bob to read that immortal document every chance he has, and the bigger the crowd, the louder he must holler.'"

...if it actually happened (???). I read it here:

http://www.mrlincolnandthefounders.org/i...ubjectID=2

The source given on the site is:
Gabor S. Boritt, editor, The Historian’s Lincoln: Pseudohistory, Psychohistory, and History, p. 132 (Glen E. Thurow).

Does anyone know the original source? I've never read it before and it's not in any of the books I have.

Why should Robert have feared reading the DOI (which his father so favored much) without permission? Abraham Lincoln was said having been an indulgent father and not one to fear at all.