Musnad Ahmad 32:267

Waki’ narrated to us, ‘Ikrimah ibn ‘Ammar narrated to me, from Ishaq ibn ‘Abdullah ibn Abi Talhah, from Anas ibn Malik, who said: Umm Sulaym came to the Prophet, peace and blessings of Allah be upon him, and said: "O Messenger of Allah, teach me words that I may supplicate with." He said: "Exalt Allah (say *SubhanAllah*) ten times, praise Him (say *Alhamdulillah*) ten times, and magnify Him (say *Allahu Akbar*) ten times. Then ask for your need, for He says: 'I have done so, I have done so.'"