Ṣuḥba: Companionship
Al-Ghazali gives whole chapters to friendship, since company shapes a person faster than any argument does. Someone you sit with weekly for years starts setting what strikes you as normal, funny, or worth having. Nobody talks you into a new direction; you drift there because the people closest to you are already headed that way.
A person follows the way of their close friend, so each of us should look at whom we befriend: close ties set direction
The saying comes from the Prophet, and Sufi teachers reach for it whenever friendship comes up. Its weight falls on the tie nobody examined, the partner chosen for money, comfort, or plain loneliness. Years pass, and a person ends up standing near where that friend stands, wanting roughly what they want.
Waraʿ: Holding back from what is unclear
Waraʿ is the habit of backing away while a thing is still only questionable. Most compromising arrangements begin as reasonable ones, with decent people and good reasons on the table. Leaving early costs a little awkwardness, while leaving after years of shared money and shared life costs nearly everything.
Ikhlāṣ: Purity of intention, one aim with nothing mixed into it
Al-Ghazali spends a whole book on how easily a second motive slips in beside the first. A close tie pointing elsewhere splits a person the same way: part of you wants one thing, part wants another. Neither half gets your full strength, and both aims come out weaker than if you had picked one.
Nūr: Light
In the Niche of Lights, al-Ghazali holds that only God's light shines on its own, and everything else borrows it. Darkness carries no force of its own; whatever the light has not reached simply stays unseen. Some company leaves a person able to tell right from wrong, and some quietly takes that seeing away.