Sahih Muslim – Hadith No : 1866

Anas reported that the Messenger of Allah (may peace be upon him) entered the mosque (and he found) a rope tied between the two pillars; so he said: What is this? They said: It is for Zainab. She prays and when she slackens or feels tired she holds it. Upon this he (the Holy Prophet) said: Untie it. Let one pray as long as one feels fresh but when one slackens or becomes tired one must stop it. (And in the hadith transmitted by Zuhair it is:” He should sit down.” )

Hadith In Arabic Text :

وحدثنا ابن نمير، حدثنا أبي، حدثنا سعد بن سعيد، أخبرني القاسم بن محمد، عن عائشة، قالت قال رسول الله صلى الله عليه وسلم ‏”‏ أحب الأعمال إلى الله تعالى أدومها وإن قل ‏”‏ ‏.‏ قال وكانت عائشة إذا عملت العمل لزمته ‏.‏

Chapter : The Book of Prayer (Travellers) – كتاب صلاة المسافرين وقصرها