The following is from Asa's pension file, found on footnote.com. Asa did not collect a pension or the land bounty offered him. However, after his death his wife Sarah did apply for the pension. The following affidavit is from their son Galen.
I Galen Foster a resident of Erie in the County of Erie and State of Pennsylvania a son of Asa Foster late of Canterbury in the County of Merrimack and state of New Hampshire deceased, testify, and say, that since my earliest recollection I have often heard my father the said Asa Foster say that he was a soldier in the Revolutionary army at West Point in the State of New York at the time of General Arnold's treason, and that he saw Arnold go down the river in a boat at the time he fled to the British, and that he was on General Arnold's lifeguard a few days before that event, but that at the time that event took place he was unwell and excused from that duty. I have frequently heard him speak of seeing Gen. Washington at West Point shortly after Arnold left.
I have many times heard my father say that he served under Captain Webster father of the late Honorable Daniel Webster of Massachusetts deceased I have also heard him mention the name of his Colonel but as it was not one with which I was historically acquainted, as in the case of Capt. Webster, I do not recollect it.
I have often hear him mention incidents of his march from Amherst in the state of New Hampshire to West Point and when he has known of my passing through Springfield Mass he has often inquired of some large elm trees which made an impression on his mind at the time he passed there in his march, were still standing. On the 4th of July last (1861) he mentioned in his family that it was just eighty one years that day since he enlisted in the Revolutionary army. He then stated he enlisted at Canterbury and that he was at the time just fifteen years and one month and one day old at the time. He then stated that his father went down to Amherst New Hampshire riding one horse and leading another for him to ride home on thinking that he was so small that he would be rejected when he got to Amherst.
I have many times heard my father, in answer to inquiries of his friends, why he did not apply for a pension, say that he held that all war was wrong, and therefore it would be wrong to receive a pension for having been a soldier - after that passage of the Act of Congress giving bounty lands to soldiers, I asked him if he would apply for his land, he replied no that he would not, that he could see no difference between that and receiving a pension, and that he had long since settled it, in his own mind, that it would be wrong for him to receive a pension for having done wrong in going into the army and he did not wish to revise the decision he had made when his mind was strong.
I further state that my father died on the 21st of August 1861 and that my mother Sarah still survives and remains a widow. And that I have no interest in her claim to bounty land.
State of New Hampshire, Merrimack County. Subscribed and Affirmed to this twenty fifth day of April A.D. 1862 And I certify that the said Galen Foster is a credible witness and that I have no interest in this claim.
Ebenezer Batchelder, Justice of the Peace