What does the Sharia say about past missed obligatory prayers, and must they be made up?

If a prayer is missed due to a valid excuse, it must be made up (qada'), along with repentance for the delay. However, if it is left intentionally without an excuse, the preponderant opinion is that the one who abandons it has no way to make it up, and is considered a disbeliever if they abandon it entirely. If they repent and pray, they return to Islam and are not commanded to make up what they missed. Nevertheless, they are advised to perform abundant supererogatory prayers, because Islam and repentance nullify what came before them.