Question: What is the legislative ruling on shaking hands immediately following the prayer, is it a bid'ah or is it sunnah, and please explain the evidences of the ruling

Answer of the Permanent Committee:

Answer: shaking hands after the obligatory prayer recurringly (all the time), then we do not know of any basis for it. Rather, it is a bid'ah, and it has been established from the Messenger of Allaah (sallallaahu alayhi wasallam) that he said, "Whoever does an action which is not upon our affair, will have it rejected" and in another narration, "Whoever introduced into this affair of ours that which is not from it will have it rejected."

Source: Fatawa Islamiyyah (1/267), through al-Bida' wal-Muhdathaat (p. 522).

Question: What is the ruling on the continually giving salutations (salaam) and shaking hands with the Imam (leading the prayer) and those on the left and right, following every obligatory prayer?

Answer of the Permanent Committee:

Answer: Persistence in given salutation to the Imaam (of the prayer), and a person giving salutation to those on his left and right following the five prayers is an innovation, because it has not been established from the Prophet (sallallaahu alayhi wasallam), and nor from his rightly guided caliphs or any of the Companions (radiallaahu anhum). And if it had been, it would surely have been narrated to us due to the repetition of the prayer five times every day. And this (matter) would not be hidden to the Muslims because it would have been in public view. And it has been established from the Messenger of Allaah (sallallaahu alayhi wasallam) that he said, "Whoever does an action which is not upon our affair, will have it rejected" and in another narration, "Whoever introduced into this affair of ours that which is not from it will have it rejected."

Source: Fatawa Islamiyyah (1/321), through al-Bida' wal-Muhdathaat (p. 523).

Imaam al-Albaani (rahimahullaah) stated:

Shaking hands after the prayers is an innovation about which there is no doubt, unless it is between two people who had not met up prior to that (i.e. the prayer), in such a case it is a Sunnah.

Source: Silsilah al-Sahihah (1/553) through Qamus al-Bida' (p. 410). This means that if two companions had not met up prior to the prayer and then saw each other after the prayer (whether they happened to be next to each other or not), then this becomes a general issue of giving salams when meeting, and is not connected to the prayer. This is different to the one who makes it a point to give salam and shake hands with the Imam or with those on his right and left after every prayer.