While reading salat (namaj) with jamat, in magrib salat, in third raqaat, when the imam is reading the "alhamdo and then another surah" in his mind (not loudly), what we have to do?

In the name of Allah, Most Gracious, Most Merciful

Assalaamu `alaykum waRahmatullahi Wabarakatuh

In the third rak’ah of Maghrib, as well as the third and fourth rak’ahs of Zuhr, ‘Asr, and ‘Ishā’ prayers, the imām will only read sūrah Fātihah and he will not read another sūrah after it.  As for those following the imām, they will remain silent and not recite anything from the Qur’ān in all of their rak’ahs in each of the prayers.  They will only read the thanā’ in the first rak’ah. 

And Allah knows best

Wassalaamu `alaykum

Ml. Abrar Mirza,
Student Darul Iftaa

Darul Iftaa