Firishta's History (Gulshan-i Ibrāhīmī) 67.4.2

67.4.2

and they proposed, therefore, that a treaty should be made not to slaughter the helpless and unarmed inhabitants in future battles. Mahomed Shah, struck with the good sense of this proposal, took an oath, that he would not, hereafter, put to death a single enemy after a victory, and would bind his successors to observe the same line of conduct. From that time to this, it has been the general custom in the Deccan to spare the lives of prisoners in war, and not to shed the blood of an enemy's unarmed subjects. Mahomed Shah, after he had thus received satisfaction, returned to Koolburga, visiting on his way Sheikh Siraj-ood-Deen, to whose prayers, as well as to the charities sent to Mecca with his mother, he ascribed his successes over the Hindoos.