The Holy Quran: Sura Isra’a, Verse 78
Establish prayer at the decline of the sun [from its meridian] until the darkness of the night and [also] the Qur’an of the morning prayer. Indeed, the recitation of dawn is ever witnessed.
3 prayer times are mentioned, not 5: Sun’s decline, Darkness of Night and Morning Prayer.
The Holy Prophet, what did he do?
Ibn Abbas, one of the most famous narrators, says according to the Musnad of Ibn Hanbal
“The Prophet prayed in Madina, while residing there, not travelling, seven and eight (this is an indication to the seven Raka’t of Maghrib and Isha combined, and the eight Raka’t of Zuhr and `Asr combined).”
Musnad al-Imam Ibn Hanbal, vol. 1, page 221.
Also, in the Muwatta’ of Malik (Imam of Maliki sect), vol. 1, page 161, Ibn
“The Prophet prayed Zuhr and `Asr in combination and Maghrib and Isha in combination without a reason for fear or travel.”
As for Sahih Muslim, see the following under the chapter of “Combination of prayers, when one is resident”:
Ibn Abbas reported:
The messenger of Allah observed the noon and the afternoon prayers together, and the sunset and Isha prayers together without being in a state of fear or in a state of journey
Sahih Muslim, English version, Chapter CCL, Tradition #1515
Ibn Abbas reported that messenger of Allah combined the noon prayer with the afternoon prayer and the sunset prayer with the Isha prayer in Medina without being in a state of danger or rainfall. And in the hadith transmitted by Waki(the words are): “I said to Ibn Abbas: What prompted him to do that? He said: So that his(prophet’s)Ummah should not be put to (unnecessary) hardship.”
Sahih Muslim, English version, Chapter CCL, Tradition #1520
Abdullah b. Shaqiq reported: Ibn Abbas one day addressed us in the afternoon(after the afternoon prayer) till the sun disappeared, and the stars appeared, and the people began to say: Prayer, prayer. A person from Banu Tamim came there. He neither slackened nor turned away, but (continued crying): Prayer, prayer. Ibn Abbas said: May you be deprived of your mother, do you teach me sunnah? And then he said: I saw the messenger of Allah(may peace be upon him) combining the noon and afternoon prayers and the sunset and Isha prayers. Abdullah b. Shaqiq said: Some doubt was created in my mind about it. So I came to Abu Huraira and asked him(about it) and he testified his assertion.
Sahih Muslim, English version, Chapter CCL, Tradition #1523
Abdullah b. Shaqiq al-Uqaili reported: A person said to Ibn Abbas(as he delayed the prayer): Prayer. He kept silent. He again said: Prayer.
He again kept silent, and he cried: Prayer. He again kept silent and said: May you be deprived of your mother, do you teach us about
prayer? We used to combine two prayers during the lifetime of the messenger of Allah(may peace be upon him).
Sahih Muslim, English version, Chapter CCL, Tradition #1524
Ibn Abbas reported: The messenger of Allah(may peace be upon him) observed the noon and afternoon prayers together in Medina without being in a state of fear or in a state of journey. Abu Zubair said: I asked Sa’id[one of the narrators] why he did that. He said: I asked Ibn Abbas as you have asked me, and he replied that he[the Holy prophet] wanted that no one among his Ummah should be put to
Sahih Muslim, English version, Chapter CCL, Tradition #1516
Ibn Abbas reported that the Messenger of Allah(may peace be upon him) observed in Medina seven (rakahs) and eight(rakahs), i.e., (he
combined) the noon and afternoon prayers(eight rakahs) and the sunset and Isha prayers(seven Rakahs).
Sahih Muslim, English version, Chapter CCL, Tradition #1522
Reference: Ref – http://www.al-Islam.org/encyclopedia/chapter7/5.HTML