He had lived long enough
There are so many missionaries going home for their health, or for some other cause, that I should be very unwilling to do so, unless my brethren and the Board thought it a case of absolute necessity. I should be of no use to the cause at home, not being able to use my voice. And, lastly, I am in my fifty-first year. I have lived long enough. I have lived to see accomplished the particular objects on which I set my heart when I commenced a missionary life; and why should I wish to live longer? I am unable to preach; and, since the last relapse, the irritation of my throat is so very trouble some that I cannot converse but with difficulty, or even sit at the table, as I have done to-day, and prepare copy for the press.
Horatius Bonar, A Missionary of the Apostolic School: Being the Life of Dr. A. Judson of Burmah (London: J. Nisbet & Co., 1871), 268.