Explanation of the words of Ibn Malik (may Allah have mercy on him): "And where they decline, they are two particles *** just as they are, if they are in the accusative, two verbs."

The Shaykh : If they cause the noun following them to be in the genitive case, they are two particles, meaning: two prepositions of the genitive. And if they cause the noun to be in the accusative case, they are two verbs. This is one of the peculiarities of the language, where a single word is sometimes used as a verb and sometimes as a preposition. If someone were to say, "This is not peculiar, do you not say 'Zayd rose' and 'the goods are upon Zayd'?" The answer is: Yes, we say that. But there is a difference between "Zayd rose" and "the goods are upon Zayd," even in writing. How is "Zayd rose" written?
The student: With an alif.

The Shaykh : With an alif, and "upon Zayd" is written with a yā. So, this is not that. There is a difference between them. The only case where they are now the same in their wording and form is that they are used as a particle and they are used as a verb. The sign of that is what the author indicated:
"And where they decline, they are two particles *** just as they are, if they are in the accusative, two verbs".