What is the ruling on greeting disbelievers with "peace" (Salam)?

Scholars differed concerning the ruling on initiating Salam (greeting) with a disbeliever and returning it:

- The majority of scholars, from the early generations (Salaf) and later ones (Khalaf), held the view that it is forbidden to initiate Salam and obligatory to respond with: "Wa 'alayk" (and upon you) or "Wa 'alaykum" (and upon you all); based on the saying of the Prophet, peace be upon him: "Do not initiate Salam with Jews and Christians..." - A group of scholars held the view that it is permissible to initiate Salam and return it to them, but using the singular form: "Al-Salamu 'alayk" (peace be upon you - singular) or "Al-Salamu 'alaykum" (peace be upon you all - plural). - A group of scholars held the view that it is permissible to initiate Salam out of necessity, need, or for a hoped-for religious benefit.

The preponderant view is that it is forbidden to initiate Salam with disbelievers in a Muslim land. However, if a Muslim is in a land of disbelief, it is permissible for him to initiate Salam and return it to ward off harm. It is more appropriate to use words of greeting other than the word Salam.