Inna lillahi wa inna ilayhi raji'un (إِنَّا لِلّهِ وَإِنَّـا إِلَيْهِ رَاجِعونَ)
It is part of the Quran, Sura Al-Baqara, Verse 156.
The full verse is as follows:
الذين اذا اصابتهم مصيبة قالوا انا لله وانا اليه راجعون "Who, when a misfortune overtakes them, say: 'Surely we belong to Allah and to Him shall we return'." [1]