Is snapping the thumb during the Tashahhud permissible in Sharia, especially since some move it up and down believing that this is more forceful against Satan?

The pointing gesture during the Tashahhud (definition) is prescribed, and scholars differ on whether to move it. As for the hadith (definition), "It is more severe on Satan than iron," it refers to pointing with the index finger. Some scholars have deemed it weak, while others have authenticated it. Mulla Ali al-Qari interprets the hadith to mean that the pointing gesture, signifying the oneness of God, is more severe on Satan than iron. The word "pointing" does not necessarily imply movement, but those who advocate for movement rely on the hadith of Wa'il ibn Hujr, "I saw him moving it, supplicating with it," even though some have deemed this addition weak. The permissibility of movement is also supported by what has been narrated from some early Muslims, such as Ibn Abbas and Mujahid. However, tapping or moving the thumb is an error and is not prescribed.