Zayd ibn Arqam said, "I had a pain in my eyes and the Prophet, may Allah bless him and grant him peace, visited me and said, 'Zayd, if tour eyes were to go blind because of their illness, what would you do?' He said, 'I would be steadfast and reckon my reward to be with Allah.' He said, 'If that happens to your eyes and you are steadfast and reckon your reward to be with Allah, then your reward will be the Garden.'"
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ الْمُبَارَكِ، قَالَ: حَدَّثَنَا سَلْمُ بْنُ قُتَيْبَةَ، قَالَ: حَدَّثَنَا يُونُسُ بْنُ أَبِي إِسْحَاقَ، عَنْ أَبِي إِسْحَاقَ قَالَ: سَمِعْتُ زَيْدَ بْنَ أَرْقَمَ يَقُولُ: رَمِدَتْ عَيْنِي، فَعَادَنِي النَّبِيُّ صلى الله عليه وسلم ثُمَّ قَالَ: يَا زَيْدُ، لَوْ أَنَّ عَيْنَكَ لَمَّا بِهَا كَيْفَ كُنْتَ تَصْنَعُ؟ قَالَ: كُنْتُ أَصْبِرُ وَأَحْتَسِبُ، قَالَ: لَوْ أَنَّ عَيْنَكَ لَمَّا بِهَا، ثُمَّ صَبَرْتَ وَاحْتَسَبْتَ كَانَ ثَوَابُكَ الْجَنَّةَ.
sunnah.com