Johannes Reuber, a grenadier among the Hessians captured at Trenton, remembered the generosity demonstrated by Americans after George Washington recommended kind treatment for the prisoners.
Read about it here, and consult the sources mentioned for more information
Bruce E. Burgoyne, Enemy Views: The American Revolutionary War as Recorded by the Hessian Participants (Bowie, Maryland: Heritage Books, 1996).
William M. Dwyer, The Day is Ours!: November 1776-January 1777: An Inside View of the Battles of Trenton and Princeton (New York: Viking Press, 1983).