Sayyiduna Abu Umamah (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Complete standing guard is forty days. Whoever stands guard for forty days, without buying or selling during that time and without committing any hadath (wrongful act), comes out of his sins like the day his mother gave birth to him."
Al-Tabarani recorded it; its chain contains Ayyub bin Mudrik, who is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجهاد / 9503
Hadith Gradingمحدثین:ضعیف جداً
Hadith Takhrij«اخرجه الطبراني فى المعجم الكبير (7605) ، أخرجه المعجم الكبير للطبراني برقم: 7606»