This had?th states clearly the prohibition of commencing any Sunnah [or N?filah] Sal?t when the Iq?mah is being recited. This opinion is held by Ash-Sh?fi‘? and the Jumh?r. (1)

Ibn Abdil Barr held the same opinion. He said: ‘In controversial matters, the strongest of all opinions is the one which has a proof from the Sunnah. [I believe that] when Iq?mah is being recited, no one should commence a N?filah Sal?t but after doing the obligatory one for the Iq?mah statement “Hayya ‘Alas Sal?t” : that is : ‘come to Sal?t’ urges a muslim to occupy himself with performing the obligatory Sal?t. Accordingly, occupying one self with that which is obligatory is better than anything else’. (2)

Al-Q?d? presented a rationale for this prohibition that through the passage of time people would believe in the obligation of preceding the obligatory Sal?t with Nafilah.

An-Nawaw?, however, believed that this rationale is untrue. He said: ‘The real rationale is to free one self from any other act to be fully occupied with the obligatory Sal?t from its beginning.

If one occupied oneself with the N?filah, he would miss Takb?ratul Ihr?m with the Im?m; accordingly, he would miss a part of the obligatory acts which have more right to be done perfectly.

Al-Qad? stated another rationale which is to maintain the unity of muslims with their Im?m. This leads us to the other mistake many muslims do when they come to the mosque and see that the Im?m had already begun the Sal?t; they move aside and do Sunnah Sal?t so quickly without concentration then join the Im?m, maybe, at the end of his Sal?t.

Doing so, they think they have won the rewards of both Sal?ts, which is impossible. This act indicates their lack of knowledge and misunderstanding for the rulings of their religion. (3)