He reported God's messenger as saying, "The inhabitants of hell will be drawn up in line, and when one of the inhabitants of paradise passes them one of them will say, `So and so, do you not recognise me? I am the one who gave you a drink.' And one of them will say, `I am the one who gave you water for ablution.' He will then intercede for him and bring him into paradise." Ibn Majah transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: " يُصَفُّ أَهْلَ النَّارِ فَيَمُرُّ بِهِمُ الرَّجُلُ مِنْ أَهْلِ الْجَنَّةِ فَيَقُولُ الرَّجُلُ مِنْهُمْ: يَا فُلَانُ أَمَا تَعْرِفُنِي؟ أَنَا الَّذِي سَقَيْتُكَ شَرْبَةً. وَقَالَ بَعْضُهُمْ: أَنَا الَّذِي وَهَبْتُ لَكَ وَضُوءًا فَيَشْفَعُ لَهُ فَيُدْخِلُهُ الْجَنَّةَ ". رَوَاهُ ابْنُ مَاجَه
sunnah.com