Is the forefinger raised and moved between the two prostrations when supplicating, as in the Tashahhud, and is this statement, which was attributed to Sheikh Ibn Uthaymeen but not mentioned by him in "Ash-Sharh Al-Mumti‘", acted upon?

Scholars differed on how to place the hands between the two prostrations. Some held the view of clenching the fist and pointing with the index finger, similar to what is done in the Tashahhud, while others maintained that the hands should be open.

Ibn al-Qayyim mentioned that the Prophet (peace be upon him) would sit in the iftirash position, place his hands on his thighs, and clench his fingers except for the index finger, then raise it and move it.

As for Sheikh Ibn Uthaymeen, he was of the opinion that the Sunnah indicates clenching the right hand, pointing with the index finger, and moving it during supplication, citing the hadith of Wa'il ibn Hujr as evidence. He believed that the hadith ("When he sat in prayer") is general and includes all sitting postures, and that the specification of some narrations to the Tashahhud does not indicate exclusivity but rather an emphasis on mentioning it.