Verily Dadhyak Atharvana proclaimed this honey to the two Asvins, and a Rishi, seeing this, said: 'He (the Lord) made bodies with two feet, he made bodies with four feet. Having first become a bird, he entered the bodies as purusha (as the person).' This very purusha is in all bodies the purisaya, i.e. he who lies in the body (and is therefore called purusha). There is nothing that is not covered by him, nothing that is not filled by him.

In plain words: The poet says the Lord made bodies with two feet and four feet, and then entered them as the person living inside. This person, called purusha, "the one who dwells in the body," fills and covers everything; nothing is without him.