Sayyiduna Abu Mas'ud (may Allah be pleased with him) said: Jibril (peace be upon him) came down to the Prophet (peace and blessings be upon him) with the times of prayer and gave him (peace and blessings be upon him) the command, so he (peace and blessings be upon him) prayed Zuhr when the sun had declined; then he prayed Asr when the shadow of everything had become equal to its measure; then he prayed Maghrib when the sun had set; then he prayed al-Atamah, which is Isha, when the redness of twilight had disappeared; then he prayed Subh when the dawn had broken. Then he came to him (peace and blessings be upon him) the next day, and he (peace and blessings be upon him) delayed Zuhr until (the shadow was) the measure of its object, and delayed Asr until (the shadow was) twice its measure; then he prayed Maghrib when the sun had set; then he prayed Isha in the darkness; then he prayed Subh when it had become light. Then he said: "Between these two is the time of prayer."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1709
(a) It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Jibril (peace be upon him) led me in prayer twice near the House (of Allah). He led me in Zuhr when the sun had declined and (the shadow) was the size of a sandal strap; then he led me in Asr when the shadow of everything had become equal to it."
(b) He narrated the hadith, and in it he said: "Then the next day he led me in Zuhr when the shadow of everything had become equal to it; then he led me in Asr when the shadow of everything had become twice its length."
(c) He then narrated the hadith, and at its end it says: Then he turned to me and said: "O Muhammad! This is the time of the prophets before you, and the time is between these two times."
(d) The position of Imam al-Shafi'i (may Allah have mercy on him) is that the beginning of the time of Asr is separate from the end of the time of Zuhr, and that the statement of Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "He led me in Asr when the shadow of everything was equal to it," means: when the shadow of everything had fully become equal to it and had exceeded that by the smallest amount. And it reached me from some of the students of Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that there is a narration with the meaning of what I have described, and I think he reported it from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1710
(a) It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the time of Zuhr lasts until Asr, that of Asr until Maghrib, that of Maghrib until Isha, and that of Isha until Fajr.
(b) Sayyiduna Ibn Abbas (may Allah be pleased with them both) said concerning the time of Zuhr: The time of the Zuhr prayer is from the declining of the sun until the Asr prayer; whenever within that time you pray, you have caught it.
(c) And the meaning that Imam al-Shafi'i (may Allah have mercy on him) described is also established from the Sunnah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1711
It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "The time of Zuhr is when the sun has declined and a man's shadow has become equal to his length, as long as the time of Asr has not come; the time of Asr is as long as the sun has not turned yellow; and the time of Maghrib is as long as the redness of twilight has not disappeared." Shu'bah said: As long as the glow (thawr) of the twilight has not faded. "And the time of Isha is between you and the middle of the night, and the time of Subh is from when dawn breaks, as long as the sun has not risen."
Shu'bah said: Sometimes he narrated it as marfu' (from the Prophet) and sometimes he did not.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1712
(a) Abu Bakr bin Abi Musa narrates from his father (may Allah be pleased with him) that a man came to the Prophet (peace and blessings be upon him) and asked about the times of prayer, and he (peace and blessings be upon him) gave him no answer. Then he ordered Bilal (may Allah be pleased with him), who called the iqamah when the dawn broke, and he (peace and blessings be upon him) led the prayer. Then he (peace and blessings be upon him) ordered him, and he called the iqamah for Zuhr while someone was saying: Has the sun declined or not? And he (peace and blessings be upon him) knew better than them. Then he (peace and blessings be upon him) ordered, and he called the iqamah for Asr while the sun was high. Then he (peace and blessings be upon him) ordered, and he called the iqamah for Maghrib when the sun had set. Then he (peace and blessings be upon him) ordered, and he called the iqamah for Isha at the time the redness of twilight disappeared. Then the next day he prayed Subh while someone was saying: Has the sun risen or not? And he (peace and blessings be upon him) knew better than them. And the next day he led Zuhr close to the time of the previous day's Asr, and led Asr while someone was saying: The sun has turned red; and he led Maghrib before the redness of twilight disappeared, and led Isha in the first third of the night. Then he said: "Where is the one who asked about the time? Between these two times is the time of prayer."
(b) In Sahih Muslim it says: Then he (peace and blessings be upon him) delayed Zuhr until he offered it close to the time of the previous day's Asr.
(c) In this there is evidence for the correctness of the interpretation of Imam al-Shafi'i (may Allah have mercy on him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1713