The Messenger of Allah ﷺ said: The prayer of a person who does not perform ablution is not valid, and the ablution of a person who does not mention the name of Allah (in the beginning) is not valid.
قَالَ رَسُولُ اللَّهِ ﷺ لاَ صَلاَةَ لِمَنْ لاَ وُضُوءَ لَهُ وَلاَ وُضُوءَ لِمَنْ لَمْ يَذْكُرِ اسْمَ اللَّهِ تَعَالَى عَلَيْهِ