The rhetorical reasoning is that an ordinary possession of a trait does not naturally suggest an additional complete bearer of it. The speaker therefore imagines a second equally qualified figure emerging from the first, implying abundance or perfection of the original trait.
Stage 1: An original person possesses the characteristic.
Stage 2: Another matching bearer is figuratively extracted from that person.
Stage 3: The audience perceives intensified possession of the trait.
Thus tajrīd is not merely repeating an adjective: the conceptual act of extracting a second counterpart is essential.