Know O pious brother – may ALLAH make our affairs good – that the manners of companionship and good relationships are of various types, of which I will explain, such as will show the person of intellect the manners of the Believers and the Pious; and com to know that ALLAH the Most Perfect, the Most High has made them a mercy and helpers towards each other, which is why the Messenger of ALLAH(saws) said, “The example of the Believers, in their mutual love and mercy is like the example of a body, if one part feels pain, then all of the body suffers in sleeplessness and fever.’
And he (saws) said, “The Believer to the Believer is like a solid building, one part supporting the other.”
The Prophet (saws) also said, “The souls are arrayed armies, so those who knew each one another before, will be friendly…”
So if ALLAH intends good for his servants, He grants them companionship of the people of the Sunnah, righteousness and adherence to the Religion; and keeps him free from the companionship of the people of innovations. The Prophet (saws) said, “A person is upon the religion of his friend, so let every one of you look to whom he keeps as friends.”
