The Messenger of Allah said: "There is no ablution for one who does not mention the Name of Allah (before doing it)." (Using translation from Ibn Mājah 397)  

عَنِ النَّبِيِّ ﷺ قَالَ «لَا وُضُوءَ لِمَنْ لَمْ يَذْكُرِ اسْمَ اللَّهِ عَلَيْهِ»