وَلَكُمْ فِي الْقِصَاصِ حَيَاةٌ
And for you in just retaliation there is life.
A brief expression carries an extensive meaning about public protection, an example of ījāz al-qaṣr. A plain assertion such as “Zayd came” may illustrate proportion between wording and intended sense.
Iṭnāb adds wording for a genuine benefit—clarification, emphasis, correction of a possible misunderstanding, and similar purposes. Mere verbosity without benefit is not a rhetorical merit.