Is the recitation of Surat Al-Mulk before sleep obligatory, or is it permissible to recite it throughout the day, and would it be considered an innovation (bid‘ah) if it is recited every day in two rak‘ahs before sleep with the intention of it being part of the night vigil (qiyam al-layl)?

The hadith (definition) indicates the importance of reciting Surat Al-Mulk every night before sleeping, and that the Prophet, peace and blessings be upon him, would not sleep until he had recited it, and that it prevents the torment of the grave. It is recommended for a Muslim to perform ablution and sleep in a state of purity. He may pray two rak'ahs after his ablution, and it is not an innovation to always recite Surat Al-Mulk in them.