«ما مات من كرم الزمان فإنّه يحيا لدى يحيى بن عبد الله»
The generosity of the age has not died; it lives with Yaḥyā ibn ʿAbd Allāh.
«يحيا» is a present-tense verb meaning “lives,” whereas «يحيى» is a proper name. Closely matching pronunciation links different grammatical categories, yielding the mustawfā variety of complete jinās.
The effect is not mere repetition of the idea of living: praise is strengthened by the elegant connection between the verb and the praised individual’s name. The difference from mumāthil lies especially in grammatical class.