Firstly: 

It is proven that the Prophet (peace and blessings of Allaah be upon him) used to point with his index finger and move it during the tashahhud when praying. 

The scholars differed concerning that and there are several points of view. 

1 – The Hanafis say that the finger should be raised when saying “Laa (no)” in the phrase “Ash-hadu an laa ilaaha ill-Allaah (I bear witness that there is no god except Allaah)” and it should be lowered when saying, “ill-Allaah (except Allaah).”  

2 – The Shaafa’is say that it should be raised when saying “ill-Allaah.” 

3 – The Maalikis say that it should be moved right and left until one finishes the prayer. 

4 – The Hanbalis say that one should point with the finger when saying the name of Allaah, without moving it. 

Shaykh al-Albaani (may Allaah have mercy on him) said: There is no basis for any of these definitions and manners in the Sunnah. The closest of them to the correct view is the Hanbali view, were it not that they limited raising the finger to when saying the name of Allaah.

Tamaam al-Minnah, p. 223. 

Secondly: 

With regard to the evidence concerning this issue: 

(a) It was narrated that ‘Abd-Allaah ibn al-Zubayr said: When the Messenger of Allaah (peace and blessings of Allaah be upon him) sat during the prayer, he would place his left foot between his thigh and calf, and tuck his right foot underneath him, and place his left hand on his left knee, and place his right hand on his right thigh, and point with his finger.

Narrated by Muslim, 579. 

In al-Nasaa’i (1270) and Abu Dawood (989) it says: “He used to point with his finger when making du’aa’ but he did not move it.” 

This addition – “but he did not move it” – was classed as da’eef by Ibn al-Qayyim in Zaad al-Ma’aad, 1/238. It was also classed as da’eef by al-Albaani in Tamaam al-Minnah, p. 218. 

(b) It was narrated that Waa’il ibn Hajar said: I said: I will certainly watch how the Messenger of Allaah (peace and blessings of Allaah be upon him) prays. So I watched him and he stood up and said takbeer (“Allaahu akbar”), and raised his hands until they were level with his ears. Then he placed his right hand on his left hand, wrist and lower forearm. When he wanted to bow, he raised his hands likewise, and put his hands on his knees, and when he raised his head he raised his hands likewise. Then he prostrated and put his hands level with his ears, then he sat with his left foot tucked underneath him and put his left hand on his left thigh and knee, and he put the edge of his right elbow on his right thigh. Then he held two of his fingers and made a circle, then he raised his forefinger and moved it, making du’aa’ with it.

Narrated by al-Nasaa’i, 889; classed as saheeh by Ibn Khuzaymah, 1/354; Ibn Maajah, 5/170; classed as saheeh by al-Albaani in Irwa’ al-Ghaleel, 367. 

Shaykh Ibn ‘Uthaymeen quoted this hadeeth – “moving it, making du’aa’ with it” – as evidence that moving the forefinger during the tashahhud should be done with every phrase of the du’aa’. He said in al-Sharh al-Mumti’: 

The Sunnah indicates that he should point with it when making du’aa’, because the wording of the hadeeth is “moving it, making du’aa’ with it”. So every time you make du’aa’, move your finger thus indicating the exalted nature of the One to Whom you are addressing your du’aa’s. So we say: 

“Al-salaamu ‘alayka ayyuha’l-Nabiyyu (peace be upon you, O Prophet)” – you should point your finger because this salaam is a kind of du’aa’. “Al-salaamu ‘alayna (peace be upon us)” – you should point your finger. “Allaahumma salli ‘ala Muhammad (O Allaah, send blessings upon Muhammad)” – you should point your finger. “Allaahumma baarik ‘ala Muhammad) O Allaah, send blessings upon Muhammad)” – you should point your finger. ‘A’oodhu Billaahi min ‘adhaab jahannam (I seek refuge with Allaah from the torment of Hell)” – you should point your finger. “Wa min ‘adhaab al-qabr (and from the torment of the grave)” – you should point your finger. “Wa min fitnat il-mahya wa’l-mamaat (and from the trials of life and death)” – you should point your finger.  “Wa min fitnat il-maseeh il-dajjaal (and from the tribulation of the Dajjaal)  – you should point your finger. Every time you make du’aa’ you should point your finger, indicating the greatness of the One to Whom you are making du’aa’. This is closer to the Sunnah. End quote. 

Thirdly: 

It is Sunnah when pointing to look at your finger. 

Al-Nawawi said: 

The Sunnah is not to let your gaze go beyond the pointing finger. There is a saheeh hadeeth concerning this in Sunan Abi Dawood. You should point in the direction of the qiblah and intend when pointing to affirm the Oneness of Allaah and exclusive devotion to Him.  

Sharh Muslim, 5/81. 

The hadeeth to which al-Nawawi (may Allaah have mercy on him) referred is the hadeeth of ‘Abd-Allaah ibn al-Zubayr quoted above. The version narrated by Abu Dawood is (989): “And he should not let his gaze go beyond his pointing finger.” Classed as saheeh by al-Albaani in Saheeh Abi Dawood. 

Fourthly: 

It is Sunnah to point with it towards the qiblah. 

It was narrated from ‘Abd-Allaah ibn ‘Umar that he saw a man moving pebbles with his hand whilst he was praying. When he finished, ‘Abd-Allaah said to him: “Do not move pebbles whilst you are praying, for that comes from the Shaytaan. Rather do what the Messenger of Allaah (peace and blessings of Allaah be upon him) used to do. He put his right hand on his thigh and pointed with the finger that is next to the thumb towards the qiblah, and he fixed his gaze on it.” Then he said: “This is what I saw the Messenger of Allaah (peace and blessings of Allaah be upon him) doing.” Narrated by al-Nasaa’i, 1160; Ibn Khuzaymah, 1/355; Ibn Hibbaan, 5/273. classed as saheeh by al-Albaani in Saheeh al-Nasaa’i. 

Fifthly: 

Bending the finger slightly when pointing was mentioned in the hadeeth of Numayr al-Khuzaa’i, narrated by A u Dawood, 991, and al-Nasaa’i, 1275. 

But this is a da’eef (weak) hadeeth. 

See Tamaam al-Minnah by al-Albaani p. 222. 

And Allaah knows best.