Question: Besides people who deny the five daily salats, there are those who claim, “Today, when the adhan for Salat al-Isha is recited, the time for Salat al-Isha expires. Though the ruling is the same in all of the four madhhabs, subsequent followers of madhhabs said that the time for Salat al-Isha lasted until the emergence of fajr. For this reason, this error must be corrected.” Have Muslims performed salats incorrectly for 1,400 years then?
ANSWER
They talk as if Islam were a newly sent religion. It is a lie and slander to say that our Master the Prophet and all Islamic scholars performed Salat al-Isha at incorrect times. Now let us have a look at pertinent Qur’anic verses, ahadith, and what Islamic scholars said concerning this matter:

The 78th verse of Surat al-Isra says (what means), "Perform salat from the time when the sun declines to the darkening of the night and at daybreak." The expressions dulook-ish-shams and ghasaq-il-layl that appear in the Arabic text of it refer to Salat az-Zuhr and Salat al-Asr, and Salat al-Maghrib and Salat al-Isha respectively. The salat performed at daybreak is Salat al-Fajr. (Baydawi)

The 39th and 40th verses of Surat Qaf say (what means), "Glorify your Lord before the rising and setting of the sun and at night." What is meant by "… before the rising of the sun" is Salat al-Fajr, and what is meant by "… before the setting of the sun" is Salat az-Zuhr and Salat al-Asr. Salat al-Maghrib and Salat al-Isha are meant by "… at night." (Baydawi)

The 114th verse of Surat Hud says (what means), “Perform salat in the two parts of the day, as well as in the early hours of the night.” The salats performed in the two parts of the day are Salat al-Fajr, Salat az-Zuhr, and Salat al-Asr. The salats performed in the early hours of the night are Salat al-Maghrib and Salat al-Isha. (Madarik)

Some hadith-i sharifs that explain the above-mentioned verses are as follows:

It is declared in the hadith-i sharifs written in Mukaddimat-us-salat, Tafsir al-Mazhari, Mizan al-Kubra, Halabi al-Kabir, and Targhib-us-salat:
(Jibril alaihis-salam led me in salat by the side of the door of the Ka’ba for two days. We two performed Salat al-Fajr as the fajr (morning twilight) dawned, Salat az-Zuhr as the sun departed from its zenith, Salat al-Asr when the shadows of things became as long as their heights, Salat al-Maghrib as the sun set [its upper edge disappeared], and Salat al-Isha when the evening twilight darkened. On the second day, we performed Salat al-Fajr when the morning twilight matured, Salat az-Zuhr as the shadows of things lengthened by twice as much as their heights, Salat al-Asr right after that, Salat al-Maghrib when the fast was broken, and Salat al-Isha at the first one-third of the night. Then he said, “O the Messenger of Allah, these are the times of salats for you and the prophets before you. Let your Ummat perform each of these five salats between the two times at which we performed each.”)

(Perform Salat al-Isha when it gets completely dark.) [Abu Dawud, Bayhaqi]

Hadrat Buraida narrates: When someone asked about salat times, the Messenger of Allah said, “Perform salats with us for two days.” Then on the first day, he performed Salat al-Maghrib after the sun set and Salat al-Isha when the brightness on the horizon vanished. On the second day, he performed Salat al-Maghrib immediately before the whiteness on the horizon disappeared, and he performed Salat al-Isha after one-third of the night passed. Then he told that person, “These are the times of salats” (Muslim, Tirmidhi, Nasai).

(Salat has a beginning and an end time. The beginning time for Salat al-Maghrib is when the sun sets. The end time of it is when the brightness on the horizon disappears. The beginning time for Salat al-Isha is when the horizon disappears, and the end of it is half of the night.) [Muslim, Tirmidhi]

Hadrat Ibn Abbas narrates: The Messenger of Allah said on the day when he delayed Salat al-Isha, “Had it not been for the fact that I would put my Ummah to trouble, I would have commanded them to perform Salat al-Isha at this time” (Bukhari, Muslim, Nasai).

It is written in credible fiqh books:

In the Hanafi Madhhab, the time for Salat al-Isha starts with the disappearance of twilight in the evening and lasts until the emergence of the time of imsak. (Halabi, Durr-ul-mukhtar, Radd-ul-mukhtar, Durar wa’l ghurar, Hindiyya, Kafi, Majmua-i Zuhdiyya)

The time for Salat al-Isha begins when twilight vanishes and lasts until the emergence of fajr, which means the end of the night. (Nimat-i Islam)

The time for Salat al-Isha begins when twilight disappears and darkness sets in. The end of the time for it is immediately before the start of the time for Salat al-Fajr. That is, it lasts until the moment when fajr as-sadiq (true dawn) emerges. (Riyad-un-nasihin)

It is written in Quduri that Salat al-Isha should be performed before one-third of the night passes. It is written in Khulasa that it is mustahab to delay Salat al-Isha until one-third of the night, mubah to delay it until half of the night, and makruh to delay it thereafter. (Sharh al-Shir’a)

It is mustahab to delay Salat al-Isha until one-third of the night. It is written in Hidaya that it is mubah to delay Salat al-Isha until half of the night. (Targhib-us-salat)

The time of Salat al-Isha begins, according to Imam-i Abu Yusuf and Imam-i Muhammad, with ’isha-i awwal, that is, when the red afterglow on the line of apparent horizon in the west disappears. The same rule applies in the other three madhhabs. (Se’adet-i Ebediyye)

For detailed information on salat times, visit http://en.turktakvim.com and http://www.namazvakti.com