Reference : Hisn al-Muslim 13

أَشْهَدُ أَنْ لا إِلَـهَ إِلاّ اللهُ 
وَحْدَهُ لا شَريـكَ لَـهُ 
وَأَشْهَدُأَنَّ مُحَمّـداً عَبْـدُهُ وَرَسـولُـه
'Ash-hadu 'an lā 'ilāha 'illallāhu 
waḥdahu lā sharīka lahu 
wa 'ash-hadu 'anna Muḥammadan `abduhu wa Rasūluhu.

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.

Reference:
Muslim 1/209.

Chapter: Upon completing the ablution