Must one make up prayers and Ramadan fasts that were missed before committing to them?

A person who intentionally abandons prayer and fasting commits a major act of disbelief (kufr akbar), unless they deny their obligation, in which case they are deemed disbelievers by scholarly consensus. If they repent and persist in prayer and fasting, their Islam is affirmed. They are not required to make up the prayers or fasts missed before their repentance, based on the Prophet’s (PBUH) saying: "Islam demolishes what came before it, and repentance demolishes what came before it." This is also because the Companions did not instruct apostates who returned to Islam to make up for missed fasting or prayers.