Assalaam alykum warahamatullaahi wabarakaatuh
Shk I have a question :
Is it allowed to fast the six days in Shawal before paying the debt of missed days in Ramadan: If yes please assist me with some authentic reference.
Imam al-Shafi`i said no, first the qada of the fard of Ramadan, then the nafl to the intention of the 6 days of Shawwal.
The authentic reference is the hadith qudsi in Sahih al-Bukhari: “My servant approaches Me with nothing lovelier to Me than what I have made obligatory upon them” to the end of the hadith. And this is the strongest and best position as the Prophet (upon him blessings and peace) also said, “Allah’s debt is the most deserving to be repaid,” which is as soon as one can, and Allah knows best.
The Shafii madhhab is the only one where you can combine prayer-intentions; however, this is valid only when combining two or more nafls with each other, such as tahiyyat al-wudu with tahiyyat al-masjid with duha for example. It is invalid for fard prayers, and qada is a fard prayer so it has to be done single-intentionally. Allahu a`lam.
Hajj Gibril Haddad