This question already has an answer here:
I believe that rashi says that the reason God made the avos/imos barren is so that they would pray since God desires the prayers of the righteous.
There's also the idea in Judaism that God is a perfect being that doesn't lack anything (a common theme in books on Jewish ethics). From my understanding a being that doesn't lack does not desire anything - you only desire something that you lack.
If so what does it mean that God desires the prayers of the righteous?