In chapter 1 of his essay Nature, Emerson writes,

The greatest delight which the fields and woods minister, is the suggestion of an occult relationship between man and the vegetable.

Emerson believes that all of nature is imbued with the divine spirit of God, and he believes likewise of humanity. Thus, there is a sort of hidden, secret relationship among all of nature and all of the human race. To know this brings Emerson, personally, a deep feeling of happiness and pleasure; it “delight[s]” him. He goes on to say that the elements of nature “nod to [him], and [he] to them,” as he feels like the divinity in himself is recognized by the divinity in these “vegetable[s]” all around him: the plants, the trees, and so on. They acknowledge his connection to God, and he acknowledges theirs.

Further, Emerson says that this is “new to [him] and old. It takes [him] by surprise, and yet is not unknown.” He likens it to when he has a “higher thought or a better emotion” come over him, like when he feels that he is “thinking justly or doing right.” This just sense of the relationship between all of the plant, animal, and human world strikes Emerson as being indicative of its accuracy. He does not doubt or question his sense of this relationship, because the feeling that it is right and true is as strong as his feeling when he does something that his morals tell him is right and just.