What is the ruling on someone who enters into a state of ihram for Umrah or Hajj while having many missed prayers, and then enters the Sacred Mosque and performs the circumambulation without first making up the missed prayers, and then makes them up after performing the rituals? Is his ritual valid despite delaying the making up of missed prayers, even though he knows it is obligatory to prioritize them based on what was transmitted from Al-Nawawi?

You must observe prayer and be careful not to abandon it, for abandoning it is a great sin. Allah Almighty has warned those who abandon it or are negligent about it in His Holy Book. Laziness in making up missed prayers is a great sin, and intentionally missing a prayer until its time expires is an even greater sin. Scholars have differed on the issue of declaring someone an infidel for abandoning prayer out of laziness, but they have agreed that abandoning prayer is a greater sin than adultery, murder, theft, and drinking alcohol. As for what is attributed to Imam al-Nawawi, that performing Tawaf (definition) (circumambulation) before making up missed prayers invalidates the Hajj or Umrah (definition), this is incorrect. Rather, it means that Tawaf is recommended for everyone entering the Grand Mosque, except for one who remembers a missed prescribed prayer; in this case, making up the missed prayer takes precedence over Tawaf. Laziness in making up missed prayers, whether at home or while traveling, does not invalidate the Hajj or Umrah.