After doing ablution well, one should say:
أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللَّهُ وَحْدَهُ لَا شَرِيْكَ لَهُ وَأَشْهَدُ أَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُوْلُهُ
اَشْهَدُ اَنْ لَّا اِلٰهَ اِلَّا اللّٰهُ وَحْدَهٗ لَا شَرِيْكَ لَهٗ وَاَشْهَدُ اَنَّ مُحَمَّدًا عَبْدُهٗ وَرَسُوْلُهٗ
Ash-hadu 'an laa 'ilaaha 'illAllahu wahdahu laa shareeka lahu wa 'ash-hadu 'anna Muhammadan 'abduhu wa Rasooluhu
I bear witness that none has the right to be worshipped but Allah alone, Who has no partner; and I bear witness that Muhammad is His slave and His Messenger (ﷺ).
Uqba bin 'Amir (RA) reported: Allah's Messenger (ﷺ) say: If any Muslim performs ablution well, then stands and prays two rak'ahs setting about them with his heart as well as his face, Paradise would be guaranteed to him.