What is the ruling on one who enters a gathering and offers a general greeting without giving a specific greeting to each of the attendees?

The questioner : Another question, my master. When a person enters upon his companions, like this, or perhaps a group of this size or larger, he says: "Peace be upon you..." and then sits down. In this situation, is it recommended that he move around and greet the group that is sitting, or—for example—should he shorten it to the phrase: "Peace be upon you..." and then sit?

The Shaykh : The answer is as follows: It is not hidden from all the attendees, I believe, that the rulings of Islamic law vary; some are obligatory, some are recommended, and there are other rulings that are not our concern right now. But regarding your question, it is obligatory for the one who enters a gathering, and it is necessary, that he offer the greeting. This is obligatory, not a recommended practice; I mean, I am pointing out the distinction between what is obligatory and what is recommended or encouraged. So, when the one who enters a gathering comes in, he must offer the greeting to the people of the gathering, and it is necessary. If he does not do so, he has committed a sin, and Allah (Mighty and Majestic) will hold him accountable for it. This is the obligation.
The role of the recommended practice comes into play in this matter; if the gathering is like this gathering, where it is easy for the one entering to shake hands with those sitting in it, then this handshake is recommended, not obligatory. If he sits down after offering the greeting, his conscience is cleared. But if he continues and shakes hands with every individual among those sitting, that is light upon light, and it carries a great reward; namely, his saying (peace and blessings be upon him): . In this lies a great virtue. And there is a hadith that the Prophet (peace and blessings be upon him)—this is a hadith from some of the Companions—who said: "We never met the Messenger of Allah...