Sayyiduna Abu Musa al-Ash'ari (may Allah be pleased with him) narrates: I heard the Prophet (peace and blessings be upon him) say this not once or twice but many times: "When a servant (regularly) does a righteous deed, and then illness or travel keeps him from that deed, the same reward is written for him as was written when he did it while healthy and resident." This hadith is sahih (authentic) on the condition of Bukhari, but the two Shaykhs did not record it in this way!