Imagine having your mother touch your cheek. Then imagine having your spouse or someone you love romantically touch your cheek. Then imagine having a baby touch your cheek. Then imagine having someone you hate and fear touch your cheek. They're very different feelings, aren't they? They all involve the same nerve endings, stimulated in basically the same ways, but with emotional content that varies to every point of the compass. This is because the sense of touch communicates and actually conveys emotion, communicates and conveys love (both good and bad) between people. That's why the Lord so often touched people as a way of healing them; through touch he could convey His love, which is life itself, to the people he touched. It's also why the people of Israel were not to touch the Ark of the Covenant -- their base loves would be conveyed to the holiness represented by the Ark.

“Earth” refers to the externals of a person or a community -- their everyday thoughts and actions -- in a broad, general sense. “Ground” refers to the parts of our external lives that are ready for cultivation, ready to be put to use. Cultivation, of course, involves loosening up the soil (breaking down our distracting habits and thoughts) and planting seeds (true concepts and ideas that spring from a desire to be good). As those seeds start growing, we begin to be truly useful. In short, then, “ground” in the Bible can mean a person or community that is receptive to the Lord's teaching. It can also mean a person or church that has received the Lord's teaching and is putting it to use.