Is it obligatory to adhere to the text of the Hadith, "Bismillah" (In the Name of Allah), when saying the tasmiyah before eating and drinking, or "La ilaha illa Allah" (There is no god but Allah) when instructing the dying, or is it permissible to add to them, such as saying "Bismillahir Rahmanir Rahim" (In the Name of Allah, the Most Gracious, the Most Merciful) or the complete Shahada?

When eating, it is prescribed to say "Bismillah" due to the narrations to that effect. As for adding "Ar-Rahman Ar-Rahim," scholars hold two opinions: The first opinion views the addition as prescribed because it is more complete, and this is the view of the Hanbali and Shafi'i jurists, and a group of Malikis. The second opinion holds that one should suffice with "Bismillah" due to the absence of specific evidence for the superiority of the addition.