Sa‘d b. ‘Ubada told God’s messenger that Umm Sa'd had died and asked him what form of <i>sadaqa</i> was best. When he replied that water was best, he dug a well and said it was for Umm Sa'd. Abu Dawud and Nasa’i transmitted it.

وَعَنْ سَعْدِ بْنِ عُبَادَةَ قَالَ: يَا رَسُولَ اللَّهِ إِنَّ أُمَّ سَعْدٍ مَاتَتْ فَأَيُّ الصَّدَقَةِ أَفْضَلُ؟ قَالَ: «الْمَاءُ» . فَحَفَرَ بِئْرًا وَقَالَ: هَذِهِ لأم سعد. رَوَاهُ أَبُو دَاوُد وَالنَّسَائِيّ