The illustrious Rishi had a Kamadhenu, (a cow yielding every thing as desired.) when she was addressed by saying "Give” she always gave what was desired.
तस्याथ कामधुग् धेनुर्वसिष्ठस्य महात्मनः। उक्ता कामान् प्रयच्छेति सा कामान् दुह्यते सदा॥