The Sunnah encourages supplicating to Allah after Wudu' and states that those who do so are among those who seek to purify themselves, as the Ayah above states. Imam Ahmad, Muslim and the collectors of Sunan narrated that `Uqbah bin `Amir said, "We were on watch, guarding camels, and when my turn to guard came, I took the camels back at night. I found that the Messenger of Allah was giving a speech to the people. I heard these words from that speech:

«مَا مِنْ مُسْلِمٍ يَتَوَضَّأُ فَيُحْسِنُ وُضُوءهُ، ثُمَّ يَقُومُ فَيُصَلِّي رَكْعَتَيْنِ مُقْبلًا عَلَيْهِمَا بِقَلْبِهِ وَوَجْهِهِ، إِلَّا وَجَبَتْ لَهُ الْجَنَّة»

(Any Muslim who performs Wudu' properly, then stands up and prays a two Rak'ah prayer with full attention in his heart and face, will earn Paradise.) I said, `What a good statement this is!' A person who was close by said, `The statement he said before it is even better.' When I looked, I found that it was `Umar, who said, `I saw that you just came. The Prophet said,

«مَا مِنْكُمْ مِنْ أَحَدٍ يَتَوَضَّأُ فَيُبْلِغُ أَوْفَيُسْبِغُ الْوُضُوءَ، يَقُولُ: أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللهُ وَأَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ، إِلَّا فُتِحَتْ لَهُ أَبْوَابُ الْجَنَّةِ الثَّمَانِيَةِ، يَدْخُلُ مِنْ أَيِّهَا شَاء»

(When any of you performs Wudu' properly and says, `I bear witness that there is no deity worthy of worship except Allah and that Muhammad is His servant and Messenger', the eight doors of Paradise will be opened for him so that he can enter from any door he wishes.)'' This is the wording collected by Muslim.