Lā ilāha illallāhwallāhu Akbar. lā ilāha illallāhu waḥdah. lā ilāha illallāhwaḥdahu lā sharīka lah. lā ilāha illallāhlahu ‘l-mulku wa lahu ‘l-ḥamd. lā ilāha illallāhwa lā ḥawla wa lā quwwata illā billāh.
There is none worthy of worship but Allah, Allah is the Most Great. None has the right to be worshipped but Allah alone. None has the right to be worshipped but Allah alone, Who has no partner. There is none worthy of worship but Allah, His is the dominion and His is the praise. There is none worthy of worship but Allah, there is no power and no might but by Allah.
Reference:
At-Tirmidhi and Ibn Majah. See also Al-Albani, Sahih At-Tirmidhi 3/152 and Sahih Ibn Majah 2/317.
Hisnul Muslim 152