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  

This tradition means that if a person performs ablution and takes a bath but does not have the intention to perform ablution for prayer and purify himself from sexual defilement, his ablution or bath is not valid.  

أَنَّ تَفْسِيرَ حَدِيثِ النَّبِيِّ ﷺ لاَ وُضُوءَ لِمَنْ لَمْ يَذْكُرِ اسْمَ اللَّهِ عَلَيْهِ أَنَّهُ الَّذِي يَتَوَضَّأُ وَيَغْتَسِلُ وَلاَ يَنْوِي وُضُوءًا لِلصَّلاَةِ وَلاَ غُسْلاً لِلْجَنَابَةِ