Explanation of the words of Ibn Malik (may Allah have mercy on him): "Or you intend the parts, and you specify with the definite *** the relative 'ayy' and the opposite, the attribute."

The Shaykh :"Or you intend the parts"
This means: you intend with "ayy" which you attached to a definite singular noun, the parts of that definite singular noun. So you say: "Which garment is better?" "Which garment is better?" Is it suitable? Its top? Say "its top." Here, you intended the parts: which part of the garment is better? And you say, for example: "Which part of the body is better?"
The student: The face.

The Shaykh : The face. Here, we intended the parts. Yes, that is correct.
The student: Which part of the sky is more beautiful?

The Shaykh : No, can you say "Which part of the sky is more beautiful?" You say: "Its stars, for example." It is permissible because you intended the parts.
"Or you intend the parts, and you specify with the definite *** the relative 'ayy' and the opposite, the attribute"
Now, "ayy" comes as a relative pronoun, as we have previously discussed in the chapter on relative pronouns, in the words of Ibn Malik:
"Ayy as" "Ayy as" It comes as a relative pronoun. Allah the Exalted said: Here, he says: The relative pronoun is restricted to the definite; it is not attached to anything but a definite noun. This is because the relative pronoun "ayy" did not occur in the Arabic language except attached to a definite noun. Therefore, it is not possible to attach it to an indefinite noun. So do not say: "I like which man stands." Instead, you say: "I like which of them stands," meaning: the one who is the most upright, as we passed through in the chapter on the relative noun. "And the opposite, the attribute" That is: the attribute comes, and when it comes as an attribute, it is not attached to a definite noun. You say: "Zayd came, a hero, right?" "Zayd came, a hero," because "ayy" here is a circumstantial phrase, and a circumstantial phrase is an attribute in meaning. And you say: "I passed by a man, a man," which is an attribute of "man," so it was attached here to an indefinite noun. Thus, if "ayy" is a relative pronoun, it is restricted to definite nouns, and if it is an attribute, it is restricted to indefinite nouns, whether it is a circumstantial phrase or a descriptive attribute, and the opposite is the attribute.