عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ: ((لَا وَضُوءَ لِمَنْ لَمْ يَذْكُرِ اسْمَ اللَّهِ عَلَيْهِ))
It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The ablution of that person is not valid who does not recite «بِسْمِ اللّٰہِ» over it."