Bukhari 4:52:85

Narrated Sahl bin Sad As-Sa'idi:

I saw Marwan bin Al-Hakam sitting in the Mosque. So I came forward and sat by his side. He told us that Zaid bin Thabit had told him that Allah's Apostle had dictated to him the Divine Verse:

"Not equal are those believers who sit (at home) and those who strive hard and fight in the Cause of Allah with their wealth and lives.' (4.95)

Zaid said, "Ibn-Maktum came to the Prophet while he was dictating to me that very Verse. On that Ibn Um Maktum said, "O Allah's Apostle! If I had power, I would surely take part in Jihad." He was a blind man. So Allah sent down revelation to His Apostle while his thigh was on mine and it became so heavy for me that I feared that my thigh would be broken. Then that state of the Prophet was over after Allah revealed "...except those who are disabled (by injury or are blind or lame etc.) (4.95)