Ihyaaud Deen An Effort to Revive Deen in Totality
عن ابن عمر رضى الله عنهما قال كان رسول الله صلى الله عليه وسلم يقول: من توضأ على طهر كتب الله له عشر حسنات. (الترغيب والترهيب 1/223)
Hazrat Abdullah ibn Umar (Radhiyallahu Anhuma) reports that Rasulullah (Sallallahu Alaihi Wasallam) said: “The one who performs (a fresh) wudhu upon wudhu (i.e. while being in the state of wudhu), Allah Ta’ala writes for him ten good deeds.”
Note: Performing a fresh wudhu upon wudhu will be permissible provided that one had performed salaah with the previous wudhu or one had carried out an ibaadat which wudhu is required for it (e.g. sajdah tilaawat). (Shaami 1/119, Fataawa Mahmoodiyah 8/124)
