Excellence of Greeting the Acquaintance Repeatedly

Imam Al-Nawawi’s Riyad-us-Saliheen
Chapter 134
Excellence of Greeting the Acquaintance Repeatedly

859. Abu Hurairah (May Allah be pleased with him)reported in the Hadith in respect of the person who was at fault in performing his Salat (prayer): He came to the Prophet (sallallaahu ’alayhi wa sallam) and greeted him. The Prophet (sallallaahu ’alayhi wa sallam) responded to the greeting and said, “Go back and repeat your Salat because you have not performed the Salat (properly).” He again performed Salat as he had prayed before and came to the Prophet (sallallaahu ’alayhi wa sallam) and greeted him. The Prophet (sallallaahu ’alayhi wa sallam) responded to the greetings (and repeated his words to him). This act of repeating (the Salat and the Salam) was done thrice.
[Al-Bukhari and Muslim].

860. Abu Hurairah (May Allah be pleased with him) reported: Messenger of Allah (sallallaahu ’alayhi wa sallam) said, “When one of you meets a brother (in Faith) he should greet him. Then if a tree or a wall or a stone intervenes between them and then he meets him again, he should greet him.”
[Abu Dawud].