It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Whoever prays one rak'ah of the Fajr prayer and then the sun rises, let him complete his prayer." Both of these chains are sahih (authentic), for both of them (Bukhari and Muslim) used Khilas bin Amr as evidence in a supporting role (shahid).

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Whoever has not prayed the two (sunnah) rak'ahs of Fajr until the sun rises, let him pray them (afterwards)." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

Sayyiduna Imran bin Husayn (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) was on a journey, and all the people slept through the Fajr prayer until they woke up because of the heat of the sun. Then they moved on a little until the sun had risen high. Then he (peace and blessings be upon him) ordered the mu'adhdhin, and he called the adhan. Then he (peace and blessings be upon him) prayed the two rak'ahs (sunnah) before Fajr. Then the mu'adhdhin called the iqamah, and he (peace and blessings be upon him) led the Fajr prayer. This hadith is sahih (authentic) according to what we have mentioned earlier, that al-Hasan's hearing from Imran is established; however, the two Shaykhs did not record the mention of repeating the sunnah prayers. It has an authentic supporting hadith (shahid) as well: