There is no such thing as a ‘good bid’ah' (innovation) as is claimed by some of the ignorant ones. Innovations – in their entirety are a going astray, as was judged by the Messenger of Allaah (Sallallaahu ‘alaihi wa sallam) in his saying:
((…Every innovation is a going astray.))* and in another narration:
((…And every going astray is in the Hell-fire.))**
As for the saying of Ameer ul Mu’mineen ‘Umar bin Al-Khattaab (radhiyallaahu ‘anhu) concerning the Taraweeh prayer: ‘What a good bid’ah this is’ – then he did not intend by this the bid’ah (innovation) in the Religion. Since he said this statement when the people gathered to pray the Taraweeh prayer, and the Taraweeh prayer is not an innovation. Rather it is a Sunnah which has been established from the Messenger of Allaah (Sallallaahu ‘alaihi wa sallam). He prayed it along with his companions on some of the nights of Ramadhaan. Then he kept away from them at the end for fear that it should seem obligatory upon them. The affair remained so during the Khilaafah of Abee Bakr, and for some time during the Khilaafah of ‘Umar, they would pray it separately whereupon ‘Umar gathered the people behind a single Imaam, just as they had gathered behind the Messenger of Allaah (Sallallaahu ‘alaihi wa sallam).
Thus ‘Umar revived this Sunnah, since the object of caution had ceased; which was: taking it as an obligation. So he revived a Sunnah – he did not come with an innovation.
Rather his saying: ‘What an good bid’ah this is’ – then his intent with that – and Allaah Knows best – was the linguistic meaning of an innovation not the Shar’ee (legislative) innovation. This is because legislative innovations are prohibited in Islaam, and the proof is based upon what we mentioned: that he intended by it the Taraweeh prayer – and the Taraweeh prayer is not an innovation – rather it is a Sunnah.
*Reported by Aboo Dawood as Hadeeth no. 4607, and At-Tirmidhee as Hadeeth no. 2676, and it was declared Saheeh (authentic) by Shaikh Al-Albaani.
**Reported by An-Nasaa’i vol 3 pages 188-189 and was declared Saheeh (authentic) by Shaikh Al-Albaani. (See his Saheeh Sunan An-Nasaa’i vol 1 page 512 Hadeeth no. 1577)