Number Nineteen (19) plays an important role in the structure of the Quran. The numerical value of the Arabic word واحد (Wahid) which means "One" is 19. Thus, number 19 represents the Oneness of God which is a very important doctrine in Islam.
When the Earth completes one rotation around the sun, the Earth will have rotated around itself 365 times while the moon will have rotated around the Earth 12 times. That is why astronomers say that the year is solar and the month is lunar. Referring to ‘Indexed Dictionary of Qur’anic Terms’ by Muhammad Fuad Abdul-Baqi, we find that the words for ‘day’ and ‘a day’- يوم and يوما- occurring in the singular are repeated 365 times, noting that one occurrence of يوم was dropped from the concordance by mistake, a fact that was pointed out in the introduction of the work. We also find that the words for ‘month’ and ‘a month’ - شهر and شهرا - in the singular are repeated only 12 times. Why are the words يوم and شهر counted in the singular?
We think that this goes back to two matters: Firstly, in Arabic a year is 365 يوم (singular), not أيام (plural). Likewise, a year is 12 شهر not شهور. Secondly, a year is one rotation of the earth around the sun and this includes 365 rotations of the Earth around itself and 12 rotations of the moon around the earth and around itself too.
Some people have objected to Abdul Razaq Nawfal not counting the words يومئذ, يومهم and يومكم . This objection is somewhat justified when there are no direct rules for counting. Here, we count يوم and يوما when it is not attached in the script to what follows it. If the word form يومئذ had been written asيوم إذ we would have counted it. In the light of this,
we count the word forms يوم and يوماbut we do not count يومئذ, يومهم and يومكم because in the Qur’anic word count we deal with script rather than meaning.
Nevertheless, we have noticed that the words يوم and يوما, يومئذ, يومهم and يومكم, and أيام and يومين occur 475 times in the Qur’an, which is the number of Earth days in 19 days of the sun. The day of any star or planet is its equal to its rotation once around itself. The day of the sun equals 25 days of the Earth so when the sun has rotates once around itself, the Earth will have revolved 25 times around itself. Consequently, when the sun completes 19 rotations around itself, the Earth will have rotated 19 x 25 = 475 times around itself . Thus, 475 is the number of Earth days in 19 days of the sun.
When the Earth rotates once around the sun, it will have rotated 365 times around itself, and the moon will have revolved around itself and the earth 12 times. Each rotation of the Earth around the sun is called one year. A year, then, is the return of the Earth to the point from which it started rotating around the sun. However, when this return of the Earth occurs,
the moon will not have returned to its starting point. Thus, “year” means return of the Earth to its starting point, but not the return of the moon. Astronomers say that the moon and the Earth meet at the same starting point once every 19 years.
In other words, it occurs when the Earth has rotated around the sun 19 times and the moon has rotated around the Earth 235 times, a rotation which astronomers call an “ecliptic cycle”. This ecliptic cycle which occurs once every 19 years has been scientifically used to match the
solar and lunar years. Hence, astronomy books about lunar and solar calendars explain the significance of this ecliptic cycle and the number 19.
Every 19 years then, we have the rotations of the Earth and the moon coincide with each other when they return to the same co-ordinate. The word سنة (year) occurs in the Holy Qur’an 7 times and سنين (years) occurs 12 times. Thus the total frequency of سنةand سنين is 19 times. It is worth pointing out at this point that every 19 lunar years contain 7 leap lunar years, which have 355 days, and 12 normal lunar years, which have 354 days.
Thus, when the Earth and the moon turn one rotation around the sun, the result is 365 rotations of the Earth around itself and 12 rotations of the moon around the Earth and around itself. It is, then, a rotation that contains sub-rotations. Similarly, the ecliptic cycle contains 19 sub-rotations of the Earth around the sun and each sub-rotations is called a year which equals about 19.58 lunar years. Hence the words سنةand سنينoccur 19 times in the Qur’an.
We can also illustrate the question in a different way: the words يوم and يوما ( both mean "day") occur 365 times in the Holy Qur’an which indicates one rotation of the Earth around the sun. Likewise, the wordsشهر and شهرا (both mean "month") occur 12 times and it is known that a month represents one rotation of the Earth around the sun. This revolution is called سنة (a year). However, when the wordsسنة and سنين occur 19 times, this seems to be a reference from Allah to the once-in-19-year ecliptic cycle which is not related only to the Earth alone but to the Earth and the moon together. While the concept of اليوم (the day) is well defined with respect to the Earth and with its relationship with the sun, the concept of السنة (a year) is multi-fold, as there are star years, tropic years, perigee years, ecliptic years… the lengths of which vary.
Hence, we find that the Quran mentions سنين (years of varying lengths) and not just سنة (year). It is also noticeable that, as mentioned earlier, سنين (years) occurs 12 times in the Holy Qur’an and that this number is the same as the number of lunar years with even-numbered total days (those years consisting of 354 days each) every 19 lunar years. As for سنة (year), it occurs 7 times, this being the number of lunar years with odd-numbered total days (those years consisting of 355 days each) which are also called leap lunar years.