Reference : Hisn al-Muslim 52

التَّحِيّـاتُ للهِ وَالصَّلَـواتُ والطَّيِّـبات ، 
السَّلامُ عَلَيـكَ أَيُّهـا النَّبِـيُّ وَرَحْمَـةُ اللهِ وَبَرَكـاتُه ، 
السَّلامُ عَلَيْـناوَعَلـى عِبـادِ للهِ الصَّـالِحـين .
أَشْـهَدُ أَنْ لا إِلـهَ إِلاّ الله ، 
وَأَشْـهَدُ أَنَّ مُحَمّـداً عَبْـدُهُ وَرَسـولُه
Attaḥiyyātu lillāhi waṣṣalawātu, waṭṭayyibāt,
assalāmu `alayka 'ayyuhan-Nabiyyu 
wa raḥmatullāhi wa barakātuh, 
assalāmu `alaynā wa `alā ‘ibādillāhiṣ-ṣāliḥīn. 
'Ash-hadu 'an lā 'ilāha 'illallāh 
wa 'ash-hadu 'anna Muḥammadan `abduhu wa rasūluh.


All greetings of humility are for Allah, and all prayers and goodness. 
Peace be upon you, O Prophet, and the mercy of Allah and His blessings. 
Peace be upon us and upon the righteous slaves of Allah. I bear witness 
that there is none worthy of worship but Allah, and I bear witness that 
Muhammad is His slave and His Messenger.

Reference:
Al-Bukhari, Muslim 1/301. See also Al-Asqalani, Fathul-Bal 1/13

Chapter: The Tashahhud