It is narrated from Sayyiduna al-Nu'man bin Bashir (may Allah be pleased with him) that he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "When one of you is about to sleep (at night) and has the intention in his heart to rise at some hour of the night and perform the (tahajjud) prayer, he should keep a heap of earth or a handful of earth with him. Then, when he wakes up, he should take a handful with his right hand and then throw it to his left side."
The chain of this hadith contains a narrator named Ayyub bin Utbah al-Yamami, who is weak; that is why the hadith scholars declared this narration da'if (weak).
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب النوافل / 588
Hadith Gradingمحدثین:إسناده ضعيف، منقطع
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :إسناده ضعيف منقطع، ومتنه منكر. » «أخرجه إتحاف الخيرة المهرة بزوائد المسانيد العشرة برقم: 1697»