سنن النسائي

It was narrated from 'Aishah, may Allah be pleased with her, that the wives of the Prophet (ﷺ) "gathered around him and said: "Which of us will be the first to following you (in death)?" He said: "The one of you who has the longest arms." They took a stick and started to measure their arms. But Sawdah was the first one to follow him. She was the one who had the longest arms, because she used to give in charity a great deal.