[1. Doing a Single Major Sin without Repenting from It]
What is well known among the people of knowledge is that a single major sin makes the one doing [it] a fāsiq [an evil doer] so long as he has not repented from it.
[2. Doing a Minor Sin Repeatedly]
As for a minor sin, it does not make him a fāsiq unless he persists and continues upon it [. . .] since his persistence upon the minor sin is an evidence of his attaching little importance to his Lord, Almighty and Majestic is He, and to His commands or prohibitions–and this is a major sin as it relates to the heart.
[3. Doing a Minor Sin Once without Due Concern for Allāh’s Law]
For this reason, it is not unfeasible for a single minor sin to be a major sin when a person does it making light of Allāh’s law, Almighty and Majestic is He, and when [he has] no concern [for it]–not [when he does it] due to desires in himself that made doing that [minor sin] something he could not resist. So a [single] minor sin can be a major one.
N.B.: Titles and headings are mine. (Trans.)