Imam Al-Nawawi’s Riyad-us-Saliheen
Chapter 135
Excellence of Greeting at the time of entry into the House

Allah, the Exalted, says:

“But when you enter the houses, greet one another with a greeting from Allah (i.e., say:  As-Salamu `Alaikum – may you be safe from evil), blessed and good.” (24:61)

861. Anas bin Malik (May Allah be pleased with him) reported: Messenger of Allah (sallallaahu ’alayhi wa sallam) said to me, “Dear son, when you enter your house, say As-Salamu `Alaikum to your family, for it will be a blessing both to you and to your family.”
[At-Tirmidhi].