Question

Salam alaykum wa rahmatullah wa barraktuhu .I am confused why in the word as in surah Al 'Ala aayah 16,  there is letter  with a small alif on top of it but is pronounced as alif.
I would appreciate if you can explain why this is so.
Jazakum Allahu khairan.

Answer

Wa alaikum as-salaam wa rahmatu Allahi wa barakatuhu. 
There are a few words in the Glorious Qur’an that are written in one way and pronounced another, and  is one of them.  Other words that are similar in that there is a written but not pronounced and instead read  with an alif are: , , , and .  The scribes of the Prophet, , wrote these words this way.  The scholar of tajweed, Sheikh Mahmammed Makki Nasr in his book “Nihaayah Al-Qowl Al-Mufeed fee ‘Ilm At-Tajweed” stated that Sheikh Ahmed bin Mubaarak in his book "Ath-thahab Al-Abreez", stated that his sheikh, the scholar, Abdulazeez Ad-Dabbaagh, was asked whether the  instead of an alif in these above words, and extra unpronounced  in other words, such as:  had originated from the Prophet or from the sahaabah; he answered that they originated from the Prophet, , and that he, , ordered the companions that wrote the revelation to write them like this.  Sheikh Ad-Dabbaagh also said this way of writing these words is considered one of the secrets of the Qur’an. 

Wa iyyakum wa al-muslimeen.