When land isn’t fertile or accepting, water just rolls away from it and nothing grows out of it. When there is a reception of water from the land, when there is an ability to absorb, then fruits, vegetables, and pasture can come out of it and benefit the land and others.
The analogy of this hadith is very powerful. The Prophet (saws) speaks of the people who aren’t able to benefit themselves or others as being ignorant and stubborn.
This is why there are certain characteristics that go hand in hand with the person who is a true student of knowledge. They need to have these characteristics so they and others can benefit from it.
Others can be exposed to ‘ilm, you could be in an Islamic university and not be a true student of knowledge. Non-Muslims can be experts in Islamic sciences, but the true people of ‘ilm are not just those exposed to it, but those who actually change within themselves and affect change in others.
There needs to be a level of humility and openness to change in the one receiving the knowledge.