Pick your friends carefully as they reflect on you, this week's sermon tells worshippers.
"Friendship is a fine human relation and a strong social bond," says the sermon, "People are naturally inclined to seek friendship out of a desire for intimacy and coexistence."
The Quran emphasised the status of friendship, putting it alongside a blood relationship, and noted that it was tested at "times of adversity".
The Prophet Mohammed once said: "A man is upon the religion of his friend, so let one of you look at whom he makes his friend."
He illustrated the influence friends have on each other in another hadith: "The similitude of good company and that of bad company is that of the owner of musk and of the one blowing the bellows.
"The owner of musk would either offer you some free of charge, or you would buy it from him, or you smell its pleasant fragrance; and as for the one who blows the bellows (i.e., the blacksmith), he either burns your clothes or you smell a repugnant smell."
A poet once said: "Ask not about the person but about who he accompanies. For everyone emulates whom he associates with."
Addressing his son, the wise Luqman said, "O my son, use your wisdom when selecting people you sit with. So if you find some who remember Allah, then join them.
"If you are knowledgeable, then your knowledge will benefit you, and if you are ignorant, they will teach you.
"What's more, Allah may bestow His mercy upon them and you will be among them.
"But if you find people who do not remember Allah, then do not sit with them. [In their presence] even if you are knowledgeable, your knowledge will be of no avail.
"And if you are ignorant, they will add to your incapacity. Allah may inflict punishment on them and you will be among them."