´It was narrated that Ibn 'Umar said:` "The Messenger of Allah said: 'It is not befitting for a Muslim who has anything concerning which a will should be made, to abide for two nights without having a written will with him.'"
Hadith ReferenceSunan an-Nasa'i / The Book of Wills / Hadith: 3645
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:إسناده صحيح