Mishkat al-Masabih 2512

He told of a man coming to the Prophet and saying that his sister had taken a vow to make the pilgrimage, but had died. The Prophet asked whether he would pay a debt, supposing she owed one, and when he replied that he would, he said, “Well, pay the debt due to God, for it is the one which most deserves to be paid.” Bukhari and Muslim.