“But when you enter houses, greet one another with peace”—that is, some of you should greet others. This applies when a man enters his own home: he should greet his family and whoever else is in his house. This was the view of Jabir, Tawus, al-Zuhri, Qatadah, al-Dahhak, and Amr ibn Dinar (1).
Qatadah said: “When you enter your home, greet your family with peace, for they are the most deserving of your greeting. If you enter a house in which there is no one, then say: ‘Peace be upon us and upon the righteous servants of Allah.’ We have been told that the angels return the greeting to him.” (2)
Ibn Abbas, may Allah be pleased with him, said: “If there is no one in the house, then let him say: ‘Peace be upon us and upon the righteous servants of Allah. Peace and the mercy of Allah be upon the people of the house.’”
Amr ibn Dinar narrated from Ibn Abbas, may Allah be pleased with him, regarding the saying of Allah Most High, “But when you enter houses, greet one another with peace”: “When you enter the mosque, say: ‘Peace be upon us and upon the righteous servants of Allah.’” (3) (4)
“A greeting from Allah, blessed and good”: this is in the accusative as a verbal noun; that is, you greet one another with a greeting—“blessed and good.” Ibn Abbas, may Allah be pleased with him, said: “Fine and beautiful.” It was also said that blessing and goodness are mentioned here because of the reward and recompense they contain.
“Thus Allah makes clear to you the signs, so that you may understand.”