Agni said: 'Friend, I will declare unto you one foot of Brahman.' 'Declare it, Sir,' he replied. He said to him: 'The earth is one quarter, the sky is one quarter, the heaven is one quarter, the ocean is one quarter. This is a foot of Brahman, consisting of four quarters, and called Anantavat (endless).

In plain words: The fire teaches him another part of Brahman. It is made of four things: the earth, the sky, heaven, and the ocean. This part is called 'Endless.'