If someone forgets the sa'i between Safa and Marwah

Hazrat Ibn Abbas (may Allah be pleased with both of them) said that if one wishes, one may perform Sa'i between Safa and Marwah, and if one wishes, one may leave it.

Hazrat Ata did not consider anything obligatory upon the one who omitted the Sa'i between Safa and Marwah. Hazrat Ibn Jurayj states that I submitted, "He has abandoned the Sunnah of the Holy Prophet (peace be upon him)." He replied, "There is nothing upon him," although he used to openly give the fatwa for sacrifice.

Hazrat Aisha (may Allah be pleased with her) said: Whoever omitted the Sa’i between Safa and Marwah, Allah the Exalted did not complete his Hajj. Then she recited this verse from the Holy Qur’an, { اِنَّ الصَّفَا وَ الْمَرْوَۃَ مِنْ شَعَآئِرِ اللّٰہِ }.