Mahabharata 3.186.124

3.186.124

tava deva śarīrasthā devadānavarākṣasāḥ |
yakṣagandharvanāgāśca jagatsthāvarajaṅgamam || 124 ||

And that boy of blazing effulgence and bearing the mark of Sreevatsa and attired in yellow robes, gratified with me, smilingly addressed me, saying, 'O Markandeya, O best of Munis, having dwelt for some time within my body, thou hast been fatigued! I shall however speak unto thee.' And as he said this to me, at that very moment I acquired a new sight, so to speak, in consequence of which I beheld myself to be possessed of true knowledge and emancipated from the illusions of the world. And, O child, having witnessed the inexhaustible power of that Being of immeasurable energy, I then worshipped his revered and well-shaped feet with soles bright as burnished copper and well-decked with toes of mild red hue, having placed them carefully on my head and joining my palms in humility and approaching him with reverence. I beheld that Divine Being who is the soul of all things and whose eyes are like the petals of the lotus. And having bowed unto him with joined hands I addressed him saying, 'I wish to know thee, O Divine Being, as also this high and wonderful illusion of thine! O illustrious one, having entered into thy body through thy mouth, I have beheld the entire universe in thy stomach! O Divine Being, the gods, the Danavas and the Rakshasas, the Yakshas, the Gandharvas, and the Nagas, indeed, the whole universe mobile and immobile, are all within thy body!