The Second Section: The Form of the Greeting of Peace and Its Meaning.

The Shaykh : The second point is: What is the form of the greeting of peace? How do I greet? Do I say, "Welcome, hello, may Allah keep you," or do I say "Hello" on the telephone, or what do I say? Or "Good morning"? What is the form of the greeting? You say, "As-salamu alaykum" (Peace be upon you), and this is the prescribed form. If you wish to add to it after saying it, you say, "As-salamu alaykum wa rahmatullah" (Peace be upon you and the mercy of Allah), or you add "wa barakatuh" (and His blessings), and that is better. Or, after you have greeted, you say, "Welcome and hello, Abu So-and-so," and there is no harm in that. For the Prophet (peace and blessings be upon him), when he was taken up in the Night Journey, would pass by the prophets and say: They would respond to him, saying after returning the greeting: except for Adam and Ibrahim, for he said, "And upon the righteous son." So the prescribed form, the prescribed form of the greeting of peace is that you say, what? "As-salamu alaykum." And what is the meaning of "As-salamu alaykum"? Is it merely a greeting, or is it a supplication and a greeting? The answer is: the latter; it is a supplication and a greeting. Because your saying "As-salamu alaykum" is a supplication for him for safety, a supplication for him for safety from every affliction, whether religious, worldly, or physical. "As-salamu alaykum" is a word that encompasses all good, for when a person is saved from evils, good and righteousness take their place.
The Third Section: What is the return of the greeting? The return of the greeting is that you say, "Alaykum as-salam" (And upon you be peace). If you say, "Welcome and hello, may Allah keep you, and may He increase you in honor and glory, wealth, and children," all of these things you mentioned do not suffice in place of saying, "Alaykum as-salam." You must say, "Alaykum as-salam," because the man supplicated for you with peace, so give him what he supplicated for you with. As He the Exalted said: Many of the common people, when you greet them, say, "Welcome and hello, Abu So-and-so." This is not sufficient. You must say, "Alaykum as-salam." Then, if you wish to follow it with whatever greetings you like, do so. And by this, we know that the greeting of peace by gesture is not a legally prescribed greeting; rather, it is prohibited to greet by gesture not accompanied by words. So if you say, "Yes, like this," then the greeting is not legally prescribed. Yes, if the person is far away or deaf and cannot hear, and you say, "As-salamu alaykum," there is no harm. But to gesture only, no. And more astonishing than that, more astonishing than the gesture, is that some people greet with the car horn. Do you know the horn? It means the car horn. Yes, they alert, and then they greet? No, no, it is not just alerting. They alert if they find a person inattentive, they alert him.
The student: ... .

The Shaykh : That is, I do not know this; I mean, he says, "Brother, mistake in expression." The correct term is to say "the warning device," but if we say "the warning device" now, in the custom of people, no one knows it. They might think it is the clock alarm that wakes you up. In any case, some people do this. But if he honks the horn and then says, "As-salamu alaykum," wanting to get his attention and then greet him, I hope there is no harm in this. But it should be limited to honking the horn. It is not permissible for one person to honk his horn and you to honk your horn at him. Who has greeted? The cars? The human being has not greeted. So in any case, the legally prescribed form is necessary: "As-salamu alaykum" and the return "Alaykum as-salam." This is the legally prescribed greeting. And thus the Prophet (peace and blessings be upon him) would greet his Companions, and they would greet him with this form.