There’s no doubt that from the completeness of (one’s) uprightness is for a person to perform what the Prophet, may Allāh send His blessings upon him and his household and grant him peace, advised with.The Prophet, may Allāh send His blessings upon him and his household and grant him peace, said:
“By Allāh, you will not enter the Jannah until you truly believe. And you will not truly believe until you love one another. Should I not inform you about something that will make you love one another when you do it? Spread the Salām (Islāmic greeting) among yourselves.”
Hence, spreading the Islāmic greetings is from the completeness of Īmān (faith). And the completeness of faith is what a person will enter the abode of paradise with.
And it is not proper for a student of knowledge, nor a youth that adheres (to the religion) to be faint (in giving the Salām). He does not give the Salām and when he does, he does so with his nose, whether it’s heard or not. And when he’s greeted, (he does not care) whether he responds or not. This is an error.
The Prophet, may Allāh send His blessings upon him and his household and grant him peace, was always cheerful and he smiled a lot, may the blessings of Allāh and peace be upon him. When what necessitates smiling occurs, he smiles. As for cheerfulness, it was constant. Always cheerful, always happy.
And there’s no doubt that when your brother meets you and he is happy with a broad face and with his face beaming, there is no doubt that he would transfer some of this happiness to you. And it’s the opposite if you meet him with a gloomy face.
So I repeat the advice, firstly to my brothers, the students of knowledge, and secondly to my brothers, the adherents (to the religion) and thirdly, to the general Muslims, to spread the Islāmic greetings among themselves.
If they want the completeness of their faith, and they want to reach (and enter) the gardens of bliss,and everyone of us want to attain that, however we have to take the means; so my advice is that they should spread the Islāmic greetings among themselves.
The youths who adhere (to the religion) and others (who are deficient), when a person meets with you, and he says the Islāmic greeting to you —even if you notice some deficiencies in his religion— you should not show that. And you say this (person) is close. And you strive to advise and get closer to him. And vice versa. Naʿam.