جَاءَنِي زَيْدٌ
Translation: Zayd came to me.
زَيْدٌ ← subject; nominative; ḍamma.
رَأَيْتُ زَيْدًا
Translation: I saw Zayd.
زَيْدًا ← direct object; accusative; fatḥa.
مَرَرْتُ بِزَيْدٍ
Translation: I passed by Zayd.
زَيْدٍ ← prepositional noun; genitive; kasra.
Remember
It is still the same person and noun. The syntactic role and the overt case vowel change. The text calls this اخْتِلَافًا لَفْظِيًّا.
Opening interactive controls...
The Rule of the Muʿrab: Visible and Estimated Case
جَاءَنِي زَيْدٌ
Translation: Zayd came to me.
زَيْدٌ ← subject; nominative; ḍamma.
رَأَيْتُ زَيْدًا
Translation: I saw Zayd.
زَيْدًا ← direct object; accusative; fatḥa.
مَرَرْتُ بِزَيْدٍ
Translation: I passed by Zayd.
زَيْدٍ ← prepositional noun; genitive; kasra.
Remember
It is still the same person and noun. The syntactic role and the overt case vowel change. The text calls this اخْتِلَافًا لَفْظِيًّا.