Ibn Malik's statement, "And omitting the surplus is permissible": We said it is permissible to omit it, whether for restriction or brevity. What does that mean?

The student: Brevity or restriction?

The Shaykh : What?
The student: "And omitting the surplus is permissible" We said: According to the author's statement, it is permissible to omit it, whether for restriction or brevity?

The Shaykh : Yes, what is known is brevity, and what is not known, which is the surplus, is restriction. This is the difference.
The student: An example?

The Shaykh : This is the example: No mention was made previously of who gives or what is feared, so this is restriction, meaning: as if he says, "Determine what you wish."