Question:
When I arrived at the mosque, I saw that the imam is already performing the obligatory prayer congregationally. Is it permissible for me to quickly perform the sunnah tahiyatul masjid prayer before joining the congregational prayer?
Answer:
Alhamdulillah, praise and thanks to Allah for the countless blessings He has blessed us all with. Blessings and salutations to the Prophet Muhammad PBUH, his wives, his family, companions and all those that follow his teachings to the day of judgement.
The sunnah tahiyatul masjid prayer is a two rakaat sunnah prayer performed when a person enters a mosque before sitting down. This is in accordance with a hadith from Abu Qatadah al-Sulami RA, where the Prophet PBUH said:
إِذَا دَخَلَ أَحَدُكُمْ الْمَسْجِدَ فَلْيَرْكَعْ رَكْعَتَيْنِ قَبْلَ أَنْ يَجْلِسَ
"If anyone of you enters a mosque, he should pray two rak`at before sitting."
Sahih al-Bukhari (444)
Answering the question, when the imam has started performing the obligatory prayer, then it is impermissible for us to perform any sunnah prayer. This is according to a hadith from Abu Hurairah RA, where the Prophet PBUH said:
إِذَا أُقِيمَتْ الصَّلاَةُ فَلاَ صَلاَةَ إِلاَّ الْمَكْتُوبَةُ
“When the Iqamah for prayer is said, there is no prayer except the prescribed prayer.”
Sahih Muslim (710)
If a ma’mum enters a mosque and the imam is already performing the prayer, then he should join the imam in prayer.
The author of the book al-Fiqh al-Manhaji stated: Any prayers; whether obligatory or sunnah prayer is considered as tahiyyatul masjid prayer. The purpose of it is so that a person would not just sit in a mosque without performing prayer first. See al-Fiqh al-Manhaji (1/525)
Thus, the obligatory prayer performed is sufficient without also performing the sunnah tahiyatul masjid prayer. The acknowledgement is the same.
May Allah SWT give us understanding in obeying all His commandment.