Kilā in Accusative and Genitive

Noun Case Classes: Type 5 — The Dual and Related Forms

رَأَيْتُ الطَّالِبَيْنِ كِلَيْهِمَا.
Translation: I saw both students, both of them.
كِلَيْهِمَا: emphatic expression, accusative with yāʾ.

مَرَرْتُ بِالطَّالِبَيْنِ كِلَيْهِمَا.
Translation: I passed by both students, both of them.
كِلَيْهِمَا: emphatic expression, genitive with yāʾ.

Result: كِلَاهُمَا is used in the nominative, while كِلَيْهِمَا is used in the accusative and genitive.