Q: I know that if you miss a waajib in prayer, you must perform sajdah-e-sahw, and if you fail to do so, you should repeat the prayer, so long as its time remains. However, once the time for the prayer is over, the prayer is not to be repeated. What is the status of missing a waajib act in a qada prayer? If you miss a waajib in a qada prayer, and you failed to perform sajdah-e-sahw (or you performed sajdah-e-sahw incorrectly, i.e. you made only one sajdah), do you then have to repeat that qada prayer? Is it merely recommended to repeat that qada prayer or is it waajib to repeat that qada prayer?
A: You should repeat the salaah.
And Allah Ta’ala (الله تعالى) knows best.