What is the ruling on the prayer led by an Imam who hastens the tasbeeh during bowing, shortens the sitting between the two prostrations, justifies this by the presence of the elderly and the sick among the worshippers, and advises those who wish to prolong their prayer to do so in supererogatory prayers?

The Imam is required to lighten the prayer for the congregants, provided that he does not compromise ṭuma'nīnah (steadiness of limbs during the pillars). If he compromises it, the prayer becomes invalid; if he observes it, the prayer is valid. Anything beyond ṭuma'nīnah is a Sunnah of the prayer. It is recommended for the Imam to lighten the prayer while still observing the Sunnahs, such as making the recitation and dhikr lighter without restricting himself to the bare minimum or fully completing the utmost. The minimum perfection in bowing (rukūʿ) and prostration (sujūd) is three glorifications (tasbīḥāt), and the most complete is eleven. The Imam must not rush to the extent that he does not perform anything beyond ṭuma'nīnah. However, if he performs ṭuma'nīnah only, without any additions, his prayer is valid for him and for those who follow him, but he would have neglected a Sunnah.