“That such an author— ay, such an authority—should espouse our cause…was a matter of no small joy, yes, exultation. … We knew that she sympathized with her brave husband in his abhorrence of our American system of slavery; but we did not know that she had so carefully studied and thoroughly mastered the subject. Nor did we suspect that she possessed the power, if she had the courage, to strike so heavy a blow.” — Samuel J. May, Some Recollections of Our Antislavery Conflict, 1869.

"[W]e would only express our ardent wish that a copy [of An Appeal] might be placed in the hands of every friend and every enemy of our cause, for the former an armory well stored with weapons...to arm him for combat in this righteous cause, to the latter the means of overcoming his opposition..." — The Liberator, reprint from the Unionist, ​​​​​​​14 Dec 1833.

“[W]hilst the thunders of…Garrison were rocking this land, and agitating it, almost all its population were as hard as the rocks… But when the melting notes of a Mrs. Child began to move upon the minds of the people…all the population that heard [her voice] seemed to melt… One Mrs. Child has done more to wake up the people to effort in this cause…than all the men that went before her in this country.” — Rev. Henry Ludlow, The Liberator, reprint from The Friend of Man, 5 Nov 1836.

Sumner, a U.S. Senator from Massachusetts, gave powerful speeches denouncing slavery, and played a vital role during the Civil War and Reconstruction.

“Many years ago I remarked, more than once, that among all antislavery pens I found most sympathy with yours. … The tone which you helped me adopt so early is most in unison with my present position.” — Charles Sumner, to Lydia Maria Child, 14 Jan 1853.

Channing, the leader of Unitarianism, was initially hesitant to speak out against slavery. His book Slavery appeared in 1835.

“Soon after The Appeal for Africans was published, Dr. Channing called upon me, for the first time, and thanked me for rousing him to the conviction that he ought not to remain silent on a subject of such vast importance.” — Lydia Maria Child, to Charles Sumner, 7 Jul 1856.

Phillips was called the ‘golden trumpet of abolition,’ known for his stirring oratory and his generous contributions to the movement.

“[I]n the winter of 1834…my beloved friend Ellis Gray Loring said to me, ‘Maria, a very talented and agreeable young man called on us last evening. He said he had been reading your Appeal, and that it made a strong impression on him. …[H]e said…that he didn’t know but he should be obliged to come out an abolitionist!’ I inquired his name and they told me it was Wendell Phillips!” — Lydia Maria Child, in Francis Jackson Garrison’s autograph book.

Higginson aided the Vigilance Committee, protecting fugitive slaves, and led a black regiment in the Civil War.

“I know that, on reading it [An Appeal​​​​​​​] for the first time, nearly ten years after its first appearance, it had more formative influence on my mind in that direction than any other.” — Thomas Wentworth Higginson, Contemporaries, 1899.

Wilson was a Massachusetts Senator, and served as Vice President under Grant.

“Mr. Wilson has recently made a...statement to Mr. Child concerning the influence of my writings on his mind.” — Lydia Maria Child, to Charles Sumner, 7 Jul 1856.

Palfrey was a clergyman, professor, and U. S. Representative from Massachusetts.

“…Dr. Palfrey told me the emancipation of his slaves grew out of the impulse which that book [An Appeal] gave to his mind.” — Lydia Maria Child, to Charles Sumner, 7 Jul 1856.