What is the ruling on greeting a passerby on the road, and is it permissible to say "ahlan" (welcome) or "marhaban" (hello/welcome) to a passerby?

Spreading peace (Saying Salaam) is one of the manifest rituals of Islam and a cause for love among Muslims. Initiating the Salaam is a Sunnah, while returning it is obligatory, based on the words of Allah Almighty: (And when you are greeted with a greeting, greet in return with one better than it, or [at least] return it [in a similar manner]). Among the etiquettes of Salaam are that the rider greets the walker, the walker greets the sitter, and the few greet the many. Saying "Ahlan wa Marhaban" (Welcome) after the Salaam is permissible, but one should not restrict oneself to it, as it is not the greeting of Islam.