When the iqamah is called, there is no prayer except the obligatory prayer.

Q: There are those who enter the mosque while the prayer is being established, but they know from the imam that he prolongs the first rak'ah; so they pray the two rak'ahs of Fajr before joining the imam. What is the ruling on that?

A: This is not permissible; because the established Sunnah of the Messenger of Allah (peace and blessings be upon him) indicates that if a ma'mum enters while the imam has already entered the prayer, he should line up, and not pray the rawatib of Fajr or any other, but rather line up with the imam; for it is established from him (peace and blessings be upon him) that he said: , which Muslim recorded in his Sahih. So it is obligatory for the one who enters while the imam has established the prayer to pray with the imam, and postpone the Sunnah to after the prayer or after the sun rises. As for praying it while the imam is praying, this is not permissible due to the aforementioned hadith.