حَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا الْهِقْلُ بْنُ زِيَادٍ السَّكْسَكِيُّ، حَدَّثَنَا الأَوْزَاعِيُّ، عَنْ يَحْيَى بْنِ أَبِي كَثِيرٍ، عَنْ أَبِي سَلَمَةَ، قَالَ سَمِعْتُ رَبِيعَةَ بْنَ كَعْبٍ الأَسْلَمِيَّ، يَقُولُ ‏:‏ كُنْتُ أَبِيتُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم آتِيهِ بِوَضُوئِهِ وَبِحَاجَتِهِ، فَقَالَ ‏:‏ ‏"‏ سَلْنِي ‏"‏ ‏.‏ فَقُلْتُ ‏:‏ مُرَافَقَتَكَ فِي الْجَنَّةِ ‏.‏ قَالَ ‏:‏ ‏"‏ أَوَغَيْرَ ذَلِكَ ‏"‏ ‏.‏ قُلْتُ ‏:‏ هُوَ ذَاكَ ‏.‏ قَالَ ‏:‏ ‏"‏ فَأَعِنِّي عَلَى نَفْسِكَ بِكَثْرَةِ السُّجُودِ ‏"‏ ‏.‏

Narrated Rab'iah b. Ka'b al-Aslami: I used to live with the Messenger of Allah (PBUH) at night. I would bring water for his ablution and his need. He asked: Ask me. I said: Your company in Paradise. He said: Is there anything other than that ? I said: It is only that. He said: Help me for yourself by making prostrations abundantly. Translation Not Available

Book Ref: Sunan Abi Dawud Book 5 Hadith 1320
Web Ref:  Sunan Abi Dawud Book 5 Hadith 1315