Chapter twenty ends on a single line that turns the whole complaint: I alone am different, and value being fed by the mother.
The image is the book's standing one for the source, appearing in chapter one, in chapter twenty-five where the nameless thing might be the mother of the world, and in chapter fifty-two where the mother is held to after the children are known. Here it is used at its most intimate, in the ordinary sense of an infant at the breast, which is prepared for by the earlier line about an infant that has not yet smiled.
What the line does is supply, in eight characters, the compensation the preceding twenty lines withheld. Everyone else is fed by the feast, which comes to an end. The speaker is fed by the source of feasts, which does not.
The chapter also opens with a line that some editors attach to the end of chapter nineteen instead: abandon learning and be free of worry. Where it belongs is a real textual question and the manuscripts do not settle it, which is one more instance of the chapter divisions being an editorial layer rather than a feature of the text.
Read with that line at its head, the chapter becomes an illustration of what abandoning learning actually costs: not serenity, but standing outside everything the people around you find sufficient, and having only the source to go on.