Narrated Ubaydullah ibn Khalid as-Sulami: The Messenger of Allah ﷺ made a brotherhood between two men, one of whom was killed (in Allah's path), and a week or thereabouts later the other died, and we prayed at his funeral). The Messenger of Allah ﷺ asked: What did you say? We replied: We prayed for him and said: O Allah, forgive him, and join him to his companion. The Messenger of Allah ﷺ said: What about his prayers since the time the other died, and his fasting since the time the other died--the narrator Shubah doubted the words, "his fasting--and his deeds since the time the other died. The distance between them is just like the distance between heaven and earth.
Hadith Referenceسنن ابي داود / كتاب الجهاد / 2524
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:حسن, مشكوة المصابيح (5286), أخرجه النسائي (1987 وسنده حسن) عبد الله بن ربيعة وثقه ابن حبان وھو مختلف في صحبته فمثله: حديثه حسن
Hadith Takhrij« سنن النسائی/الجنائز 77 (1987)، (تحفة الأشراف: 9742)، وقد أخرجہ: مسند احمد (3/500، 4/219) (صحیح) »