The Prophet said: "Whoever performs ablution and does it well, then says three times: 'Ashhadu an la ilaha illallah wahdahu la sharika lahu, wa ashhadu anna Muhammadan ʿabduhu wa rasuluhu (I bear witness that none has the right to be worshipped but Allah alone, with no partner, and I bear witness that Muhammad is His slave and His Messenger),' eight gates of Paradise will be opened for him; whichever one he wants he may enter." (Da'if) Another chain with similar wording.  

عَنِ النَّبِيِّ ﷺ قَالَ مَنْ تَوَضَّأَ فَأَحْسَنَ الْوُضُوءَ ثُمَّ قَالَ ثَلاَثَ مَرَّاتٍ أَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَحْدَهُ لاَ شَرِيكَ لَهُ وَأَشْهَدُ أَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ فُتِحَ لَهُ ثَمَانِيَةُ أَبْوَابِ الْجَنَّةِ مِنْ أَيِّهَا شَاءَ دَخَلَ قَالَ أَبُو الْحَسَنِ بْنُ سَلَمَةَ الْقَطَّانُ حَدَّثَنَا إِبْرَاهِيمُ بْنُ نَصْرٍ حَدَّثَنَا أَبُو نُعَيْمٍ بِنَحْوِهِ  

"The Messenger of Allah said: 'There is no Muslim who performs ablution and does it well, then says: Ashhadu an la ilaha illallah, wa ashhadu anna Muhammadan ʿabduhu wa rasuluhu (I bear witness that none has the right to be worshipped but Allah, and I bear witness that Muhammad is His slave and Messenger),' (except that) eight gates of Paradise will be opened for him, and he will enter through whichever one he wants.'"  

قَالَ رَسُولُ اللَّهِ ﷺ مَا مِنْ مُسْلِمٍ يَتَوَضَّأُ فَيُحْسِنُ الْوُضُوءَ ثُمَّ يَقُولُ أَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَشْهَدُ أَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ إِلاَّ فُتِحَتْ لَهُ ثَمَانِيَةُ أَبْوَابِ الْجَنَّةِ يَدْخُلُ مِنْ أَيِّهَا شَاءَ