What is the difference between the east (مشرق) in singular, dual, an plural forms?

Question

In Surat Al-Baqarah, verse 115, Allah says:

Here, Allah says that he owns Al-Mashriq (literally: the east/sunrise), in the Arabic singular form, المشرق .

In Surah Ar-Rahman, verse 17, Allah says:

Here, Allah says that he is Lord of Al-Mashriqayni (literally: the two easts/sunrises), in the Arabic dual form, المشرقين.

In Surah As-Saffaat, verse 5, Allah says:

Here, Allah says that he is Lord of Al-Mashaariq (literally: the multiple easts/sunrises), in the Arabic plural (3+) form, المشارق.

Since parts of the Qur'an explain other parts, what exactly do the scholars of tafseer (the mufassireen) explain as the interpretation of these three ayat when you look at them together as a set?

Answer 1

When you observe the sunrise for a year, you will notice that the sun rises at different locations in the east on different days of the year.

This different locations consists of

1) Two extremities in the east

The dual would imply the two extremities of the sun's positions [Al-Mashriqayni]

2) All points between two extremities

The plural (3+) would imply all the points between the two extremities [Al-Mashaariq]

3) Absolute center or Entire spectrum

The singular however could imply either the absolute center or could also imply the whole spectrum as a singular unit [Al-Mashriq]

Below see the 3 points of the sun on different days. (I.e. two extremities and absolute center)

Allah knows best...

Answer 2

According to Tafsir al-Mizan:

1) The singular Al-Mashriq refers to the whole eastern hemisphere of the earth( or even the universe)

2) The dual Al-Mashriqayn refers to two different sunrises, one in the summer and the other in the winter (which islam101 mentioned)

3) The plural Al-Mashaariq may refer to:

1. different sunrises in one place in different times of the year( again what islam101 mentioned)
2. different sunrises in different places(for example countries or cities) at a same time (pointing to the spherical earth)
3. different sunrises(?) of different stars, one of which is the sun.

Answer 3

As you noted in the question, the literal meaning of the words mashriq and maghrib is that of the place or time of sunrise and sunset, resptecively. The different usages show that the direction and time of sunset/sunrise is not fixed and constant always (which we know from experience as well). The singular is used when the emphasis is not on this plurality, and the plural is used to emphasize this fact. The dual is taken to mean the extremes and everything in between.

Reference: Tafhim al-Qur'an