Anas (May Allah be pleased with him) reported:
The Prophet ﷺ came into the mosque and noticed a rope stretched between two poles. He enquired, "What is this rope for?" He was told: "This is Zainab's rope. When during her voluntary prayer, she begins to feel tired, she grasps it for support". The Prophet ﷺ said, "Untie it. You should perform prayers so long as you feel active. When you feel tired, you should go to sleep".

[Al-Bukhari and Muslim].

وعن أنس رضي الله عنه قال: دخل النبي ﷺ المسجد فإذا حبل ممدود بين الساريتين فقال: "ما هذا الحبل" قالوا : هذا حبل لزينب، فإذا فترت تعلقت به. فقال النبي ﷺ " حلوه، ليصل أحدكم نشاطه فإذا فتر فليرقد" ((متفق عليه)) .