It is narrated from Sayyidah Kabshah bint Ka'b (may Allah be pleased with her) that she said: I used to sleep before the Isha prayer ('Atamah), and when I heard the iqamah I would wake up and pray. Then it reached me that sleeping before Isha is disliked, so I asked Sayyiduna Anas bin Malik (may Allah be pleased with him) about it, and he too disliked it and instructed emphatically: "Never sleep before the Isha prayer."
Imam Musaddad bin Musarhad (may Allah have mercy on him) mentioned this report in his Musnad. The dislike of sleeping before the Isha prayer and of needless talk after it is also established by other sahih hadith, so that the Isha prayer is not missed and the congregation is not disrupted.
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب الصلاة / 284
Hadith Gradingمحدثین:إسناده ضعيف جدًا
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :إسناده ضعيف جدًا. » «أخرجه أبو يعلى فى «مسنده» برقم: 4039، وأورده ابن حجر فى "المطالب العالية"، 284، وأخرجه ابن أبى شيبة فى «مصنفه» برقم: 6751، 7252، وأورده ابن حجر فى "المطالب العالية"، 283»