פירוש על קידושין 65:1

The rabbis claim that had the verse referred to two different people it should have applied both verbs to both types of people—the young and old sage. The fact that one verb applies to each implies that they are identical.
We should note that the Talmud spends a lot of time discussing honoring the young sage. It seems to ignore the opinion that the verse refers to any old person, even one who is not a sage.