Is it obligatory for the congregant to say "Subhan Allah" (Tasbih) during bowing (Ruku') and prostration (Sujud), or is it permissible for him to suffice with the Imam's Tasbih?

Scholars differed on the ruling of tasbih (glorification) in bowing (ruku') and prostration (sujud (definition)) into two opinions:

The first opinion: It is sunnah (definition) (recommended), and this is the view of the majority of scholars. They cited as evidence that the Prophet, peace and blessings be upon him, did not mention it to the Bedouin who did not perform the prayer well.

The second opinion: It is wajib (definition) (obligatory), and this is the view of the Hanbalis and the Zahiris. Ibn Taymiyyah, Ibn Baz, and Ibn Uthaymeen preferred this view. They cited as evidence the command for it in the prophetic hadiths, and a command implies obligation.

In summary, most scholars hold that it is not obligatory, but it is better to perform it. The minimum for perfection is three glorifications, and one glorification suffices.

For whoever does not perform tasbih, their prayer is valid according to the majority. As for those who hold it to be obligatory, they believe that if the imam or one praying alone intentionally omits it, they must repeat the prayer. If they omit it unintentionally, they must perform the prostration of forgetfulness (sujud as-sahw). As for the follower (ma'mum), they do not perform the prostration of forgetfulness, and the imam bears it on their behalf, unless they were a latecomer to the prayer.

A worshiper must never abandon tasbih and similar adhkar (remembrances) absolutely. Whoever persistently abandons it intentionally, their testimony might be rejected due to their negligence in religious matters.