It is Bidah to pray Taraweeh in Jamat. However, this is a good Bidah (Hasanah) and not blameworthy, because it was established by the great Sahabi Sayidina Umar bin al-Khattab (May Allah Most High be pleased with him).
عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَبْدٍ القَارِيِّ، أَنَّهُ قَالَ: خَرَجْتُ مَعَ عُمَرَ بْنِ الخَطَّابِ رَضِيَ اللَّهُ عَنْهُ، لَيْلَةً فِي رَمَضَانَ إِلَى المَسْجِدِ، فَإِذَا النَّاسُ أَوْزَاعٌ مُتَفَرِّقُونَ، يُصَلِّي الرَّجُلُ لِنَفْسِهِ، وَيُصَلِّي الرَّجُلُ فَيُصَلِّي بِصَلاَتِهِ الرَّهْطُ، فَقَالَ عُمَرُ: «إِنِّي أَرَى لَوْ جَمَعْتُ هَؤُلاَءِ عَلَى قَارِئٍ وَاحِدٍ، لَكَانَ أَمْثَلَ» ثُمَّ عَزَمَ، فَجَمَعَهُمْ عَلَى أُبَيِّ بْنِ كَعْبٍ، ثُمَّ خَرَجْتُ مَعَهُ لَيْلَةً أُخْرَى، وَالنَّاسُ يُصَلُّونَ بِصَلاَةِ قَارِئِهِمْ، قَالَ عُمَرُ: «نِعْمَ البِدْعَةُ هَذِهِ، وَالَّتِي يَنَامُونَ عَنْهَا أَفْضَلُ مِنَ الَّتِي يَقُومُونَ» يُرِيدُ آخِرَ اللَّيْلِ وَكَانَ النَّاسُ يَقُومُونَ أَوَّلَهُ
Abd al-Rahman bin Abd al-Qari said, I went with Umar bin al-Khattab (May Allah Most High be pleased with him) one night in Ramadan to the Masjid and found the people praying in scattered groups. A man praying alone or a man praying with a small group behind him. So, Umar (May Allah Most High be pleased with him) said, ‘I think it would be best to gather these people with one Qari (Reciter).’ When he resolved to do so, he congregated them behind Ubay bin Ka’b. On another night I went with him (Umar), and the people were praying behind their reciter. (Sayidina) Umar remarked, ‘What an excellent Bid’ah this is, but the prayer they sleep for, is better than the one they are standing for.’ He meant the prayer in the last part of the night, whilst the people were praying in the early part of the night. (Bukhari, 2010).
As seen in the Hadith above Sayidina Umar bin al-Khattab (May Allah Most High be pleased with him) gathered the people to pray in one large congregation and then he described the congregation as an excellent Bidah. Therefore, it is Bidah to pray Taraweeh in Jamat. However, this is a rare case in which Bidah is acceptable. Usually Bid’ah is strictly prohibited in Islam (see the link below for details).
إنما دعاها بدعة لأن رسول الله صلى الله عليه وسلم لم يسنها لهم، ولا كانت في زمان أبي بكر، وإنما أثنى عليها ورغب فيها بقوله: (نعم) ليدل على فضلها، ولئلا يمنع بهذا اللقب من فعلها. (أعلام الحديث)
He (May Allah Most High be pleased with him) called it Bid’ah because the Messenger of Allah ﷺ did not establish it for them, nor was it existent in the time of Abu Bakr (May Allah Most High be pleased with him). He (May Allah Most High be pleased with him) praised it and encouraged it by saying, Ni’ma (how great), to indicate its merit, and so that this label (Bid’ah) does not prevent people from doing it. (Imam Abu Sulayman al-Khattabi, Sharh Sahih al-Bukhari).
Many people have completely misunderstood this Hadith and believe it gives them licence to engage in Bidah regularly and simply label it as Bidah Hasanah when questioned about it. Such an approach is obviously erroneous and contradicts Quran, Hadith and the statements of the classical scholars of Ahl al-Sunnah. Bidah is actually a very complicated area and must be studied thoroughly to understand it correctly, and to safeguard oneself from contemporary extremes.
And Allah Most High Knows Best
-Answered by Shaykh Noorud-deen Rashid (25.04.2022)
What is Bidah?
Is every Bidah a good Bidah (Bidah Hasanah)
Did the Prophet pray Taraweh in Jamat
See also (video):