Reference : Hisn al-Muslim 125

اللهُ اللهُ رَبِّي لا أُشْـرِكُ بِهِ شَيْـئاً
Allāh, Allāhu Rabbī lā ushriku bihi shay'a.

Allah, Allah is my Lord. I do not associate anything with Him.

Reference:
Abu Dawud 2/87. See also Al-Albani, Sahih Ibn Mdjah 2/335.

Chapter: For one in distress