Prayer: Discovering Invalid Wuduʾ or Ghusl During or After Prayers
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1251
If during or after prayers one learns that his wuḍūʾ or ghusl was invalid, or that he started performing prayers without wuḍūʾ or ghusl, he must perform the prayer again with wuḍūʾ or ghusl; and if the time for the prayer has expired, he must make it up.