Muhammad bin ‘Abdullah bin Yazid said: “Sufyan narrated to from Az-Zuhri, from ‘Ubaidullah - bin ‘Abdullah, from Ibn ‘Abbas, that Saad said: ‘My mother died and there was an (outstanding) vow that she had to fulfill. I asked the Prophet صلی اللہ علیہ وآلہ وسلم and he told me to fulfill it on her behalf.” (Sahih)