وَعَنْ رَبِيعَةَ بْنِ كَعْبٍ رَضِيَ اللَّهُ عَنْهُ قَالَ: كُنْتُ أَبِيتُ مَعَ رَسُولِ اللَّهِ ﷺ فَآتِيهِ بِوَضُوئِهِ وَحَاجَتِهِ، فَقَالَ لِي: سَلْ. فَقُلْتُ: أَسْأَلُكَ مُرَافَقَتَكَ فِي الْجَنَّةِ. قَالَ: أَوْ غَيْرَ ذَلِكَ؟ قُلْتُ: هُوَ ذَاكَ، قَالَ: فَأَعِنِّي عَلَى نَفْسِكَ بِكَثْرَةِ السُّجُودِ
Translation: Rabiʿah ibn Kaʿb said: I used to stay with the Messenger of Allah ﷺ and bring him water for ablution and what he needed. He said: Ask. I said: I ask for your companionship in Paradise. He said: Or something else? I said: That is what I seek. He said: Then help me in your own case through frequent prostration.
Rabiʿah ibn Kaʿb used to attend to the Prophet ﷺ by bringing water for ablution and other necessities. When the Prophet ﷺ said, “Ask,” Rabiʿah did not request a worldly advantage: he asked for the Prophet’s company in Paradise. When asked whether he wished for something else, he affirmed the same request.
The Prophet ﷺ directed him to strive through frequent prostration. مُرَافَقَتَكَ means “your companionship,” فِي الْجَنَّةِ “in Paradise,” and بِكَثْرَةِ السُّجُودِ “through frequent prostration.”
Source: Muslim