Is reciting the verse: "Indeed, Safa and Marwah are among the symbols of Allah," and saying: "I begin with what Allah began with," at the start of each circuit of Sa'i, as well as the rest of the remembrances, a condition for the validity of Sa'i, and what are the consequences for one who fails to do so or forgets some of it?

The remembrance mentioned is authentically reported from the Prophet, peace and blessings be upon him, in the lengthy Hadith of Jabir, which describes his Hajj. It is a Sunnah (recommended practice) and not obligatory. Whoever omits it, or omits a part of it, their sa'i (ritual circumambulation between Safa and Marwah) is valid, and there is nothing upon them. Scholars have agreed that there is no specific dhikr (remembrance) prescribed for the entire duration of the sa'i; rather, it is a place for supplication. It is sunnah to stand on Safa and Marwah facing the Kaaba, to remember Allah Almighty with the aforementioned remembrance, to supplicate, and to repeat it three times. The verse "Indeed, As-Safa and Al-Marwah are among the symbols of Allah" is recited when approaching Safa at the beginning of the sa'i for the first circuit only.