Esteemed Shaikh, what is the guiding principle with regard to the difference between texts concerning greater and lesser shirk?
This [is a] question a lot of people ask about, saying: what is the difference between lesser shirk and greater shirk?
Greater shirk is that which, when it takes place from a person, he leaves the religion [of Islam, becoming a disbeliever]; lesser is that which is less than that.
So directing worship to other than Allāh is greater shirk, and revering [any of] creation as Allāh is due reverence, such that one [of creation] is given a right of divine lordship or revered as the Creator is revered, is greater shirk.
And whatever is less than that is lesser shirk, for example: the issue of swearing by other than Allāh is lesser shirk as an initial assumption. However, if there were in the heart of the one swearing, that the one he swore by was like Allāh, it becomes greater shirk.
So the guiding principle is that whatever the Shāri‘ [the One who lays down Islāmic law] calls shirk [that] does not [at the same time] take [one] out of the religion, is lesser shirk, [while] that which takes [one] out of the religion is greater shirk.
And another question [still] remains for us: what is it that takes [one] out of the religion? And what is it that does not take [one] out?
This depends on the given text, so whoever gives one of creation a right that is only for the Creator, then this is greater shirk, and whatever is less than that is lesser shirk.
I will give you an example: If a person respects his father greatly–every time he comes, he kisses his hand or kisses his forehead; sets his sandals down before him [to wear] and brings the car close to him [to save him having to walk]–this is showing great respect.
If he were to come to another person and did the same for him as he had done for his father, then this [person] has put other than his father [on] the same [level] as his father.
However, had he only presented [this person other than his father] sandals [for him to wear], would he then be treating this other one as one equal to his father? Of course not.