Question:

What is the ruling of shaking hands with a disbeliever?

Answer:

Ash-Shaykh Muhammad bin Saalih al-Uthaymeen, may Allaah have mercy upon him, was asked the ruling on shaking the hands of a kaafir:

Answer:

If he [i.e. the Kaafir] puts his hand out [to you first] then it is okay [to shake his hands], the ruling of shaking hands has the same ruling of giving salaams; you should not
start them with it but if they start [you with salaams] then you should reply to them back.

[al-Kanzuth Thameen, Print: at-Tadmuriyah]

Ash-Shaykh Saalih al-Fawzaan, may Allaah preserve him, was asked
regarding the ruling on shaking the hand of a Kaafir:

Answer:

If they give you salaams and put their hand out to you, then shake
their hands, there is nothing wrong with that. As for you starting them by giving them salaams and by shaking their hands first, then this is not permissible.

[Silsilatu Sharhir Rasaa’il, page 32. , Print :al-Imaam Ahmad]

Translated and Answered by

AbdulFattaah bin Uthman
Abu Fajr