Earlier, عُمَرُ was discussed as a proper name with ʿadl, a technical shifted form. This illustrates the joining of causes.
جَاءَ عُمَرُ — ʿUmar came; nominative subject with ḍamma.
رَأَيْتُ عُمَرَ — I saw ʿUmar; accusative object with fatḥa.
مَرَرْتُ بِعُمَرَ — I passed by ʿUmar; genitive after bi-, but marked with fatḥa because it is a diptote.
This connects the book’s previous discussion of ʿadl to the present principle.