Keep your promises and honor your commitments even if they are made by someone else or after their death; Help those who have passed away in fulfilling their obligations as much as possible; Strive for rewards from Allah SWT in the afterlife.

This hadith is about fulfilling a vow that was made by someone who has passed away. Sa'd bin 'Ubadah asked the Prophet Muhammad ﷺ for advice on what to do with a vow his mother had made but did not fulfill before she died. The Prophet ﷺ advised him to fulfill it on her behalf. This teaches us that we should be mindful of our promises and vows and strive to keep them even if they are made by someone else or after their death. We should also strive to help those who have passed away in fulfilling their obligations as much as possible so that they can receive the rewards from Allah SWT in the afterlife.