Sayyiduna Rabi'ah bin Ka'b al-Aslami (may Allah be pleased with him) said: I used to spend the night with the Prophet (peace and blessings be upon him) and bring him water for his ablution and his needs, for he (peace and blessings be upon him) would stand in prayer at night. He (peace and blessings be upon him) would say: 'Subhana Rabbi wa bi-hamdihi' (Glory be to my Lord, and all praise is His), 'Subhana Rabbi wa bi-hamdihi' (Glory be to my Lord, and all praise is His), saying it for a long while. 'Subhana Rabbi Rabbil-'alamin' (Glory be to my Lord, the Lord of the worlds), 'Subhana Rabbi Rabbil-'alamin' (Glory be to my Lord, the Lord of the worlds), saying it for a long while. Rabi'ah (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) said to me: "Do you have any need?" I said: O Messenger of Allah, I want your (peace and blessings be upon him) company in Paradise. He (peace and blessings be upon him) said: "Anything other than that?" I said: O Messenger of Allah, I want your (peace and blessings be upon him) company in Paradise. He (peace and blessings be upon him) said: "Then help me with yourself by making abundant prostrations binding upon yourself."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4568