Narrated Al-Bara:When the Verse:-- "Not equal are those of the believers who sit (at home)" (4.95) was revealed, Allah's Apostle called for Zaid who wrote it. In the meantime Ibn Um Maktum came and complained of his blindness, so Allah revealed: "Except those who are disabled (by injury or are blind or lame..." etc)
Hadith No. 4593
Sahih al Bukhari