Who is the figure from the heavens mentioned in chapter 37, and what is the point of the comparison made about him?

In chapter 37, the celestial figure mentioned is Indra, who is said to revel in the Nandana garden in heaven. He is contrasted with a donkey that wallows in a dung-heap. The text makes this comparison to illustrate that sensual pleasure is the same in essence, regardless of the being experiencing it or the environment. It states that if you look at the pleasure itself, it is of equal weight and not different in the slightest. This is used to argue why one should not strive for heavenly realms, from which one falls when merit is exhausted, and instead value the earth-world for spiritual attainment.