The wives of the Prophet ﷺ gathered around him and asked, "Which of us will be the quickest to follow you in death?"He replied, "The one with the longest hand among you."So they took a reed and began measuring their hands against it. But it was Sawdah who was the quickest to follow him in death, and she turned out to be the one with the longest hand among them, on account of her abundant charity.
أخبرنا أبو داود قال حدثنا يحيى بن حماد قال أنبأنا أبو عوانة عن فراس عن عامر عن مسروق
أن أزواج النبي ﷺ اجتمعن عنده فقلن أيتنا بك أسرع لحوقا فقال أطولكن يدا فأخذن قصبة فجعلن يذرعنها فكانت سودة أسرعهن به لحوقا فكانت أطولهن يدا فكان ذلك من كثرة الصدقة
Bukhari recorded it in the Book of Zakat, in the chapter before the chapter on giving charity openly, hadith no. 1420, from the hadith of Abu Awana with this same wording. It is also found in Al-Kubra, hadith no. 2321.