What is the ruling on returning the greeting of "Salam" to a person who has finished their prayer?

Returning a greeting is only incumbent after the greeting has been initiated. The greeting upon exiting prayer does not carry the ruling of an initiated greeting that requires a response. There is a significant difference between one who exits prayer by saying "Assalamu alaykum" and one who greets a group, meaning he greets them with salutations. The response is obligatory for those greeted in the latter case, but not the former. The Shafi'is hold that the Imam intends to greet the congregants, and they intend to return the greeting to him and to any believers who have greeted them, based on the hadith: "The Messenger of Allah (peace be upon him) commanded us to return the greeting to the Imam, to love one another, and for some of us to greet others." This was narrated by Abu Dawud, and its chain of transmission is weak.