The Index Finger In Tashahhud
Wa’il bin Hujr said: “I am going to watch the Messenger of Allah (peace be upon him) and see how he prays. So, I watched him.” And he described (his prayer): “Then he sat and lay his left foot on the ground, and placed his left hand on his left thigh and knee. He put his right elbow on his right thigh, then he made a circle with two fingers of his (right) hand, then he raised his finger and I saw him moving it, supplicating with it.” (An-Nas’i)
Therefore, it is a sunnah to point one’s index finger and move it during the tashahhud.
It is also a sunnah to point towards the qiblah (direction of prayer).
To know more about the Prophet’s guidance in pointing his index finger whenever he sat down for tashahhud during the prayer, watch this short talk with Dr. Muhammad Salah.
Source: Huda Youtube Channel.