What is the ruling on shaking hands with a person praying beside you after the prayer ends?

The questioner : Regarding the salam, some people see others giving the salam after the fire and after sleeping. It is considered valid in this country, meaning they give the salam when the prayer is finished. Some of them cited the hadith of the one whose prayer was defective, in which he repeated the salam three times to the dead.

The Shaykh : Yes. All right. Ibn al-Qayyim said, “And seek refuge in Allah from arrogance and desire, for they are the two that gather all evil.” A person who has a desire will cite evidence from what has no evidence. The one whose prayer was defective gave the salam because he turned away and then came back, so he gave the salam because it is prescribed for a person to give the salam when he meets his brother after he has turned away from him. He did not give the salam because he had completed his prayer.
As for the issue of the salam after the prayer, it falls into two categories. The first category is when a person adopts it as a recommended practice (sunnah) after the prayer. The sign of this is that he and his companion come to the mosque, they both enter, and they both pray. When he gives the salam from the prayer, he gives the salam to his companion and shakes his hand. This means that he understands that this salam is among the recommended practices of the prayer. There is no doubt that this is forbidden, and its practitioner is considered an innovator. The second category is when it is not like that, but rather he gives the salam to him out of habit and shakes his hand out of affection and bonding. There is nothing wrong with this, and the sign of this is that he does this because he did not meet him before the prayer. There is nothing wrong with this, and there is no issue with it.