SB 4.6.40

sa tūpalabhyāgatam ātma-yoniṁ
 surāsureśair abhivanditāṅghriḥ
utthāya cakre śirasābhivandanam
 arhattamaḥ kasya yathaiva viṣṇuḥ
Word for word: 
saḥ — Lord Śiva; tu — but; upalabhya — seeing; āgatam — had arrived; ātma-yonim — Lord Brahmā; sura-asura-īśaiḥ — by the best of the demigods and demons; abhivandita-aṅghriḥ — whose feet are worshiped; utthāya — standing up; cakre — made; śirasā — with his head; abhivandanam — respectful; arhattamaḥ — Vāmanadeva; kasya — of Kaśyapa; yathā eva — just as; viṣṇuḥ — Viṣṇu.
Translation: 
Lord Śiva’s lotus feet were worshiped by both the demigods and demons, but still, in spite of his exalted position, as soon as he saw that Lord Brahmā was there among all the other demigods, he immediately stood up and offered him respect by bowing down and touching his lotus feet, just as Vāmanadeva offered His respectful obeisances to Kaśyapa Muni.
Purport: 

Kaśyapa Muni was in the category of the living entities, but he had a transcendental son, Vāmanadeva, who was an incarnation of Viṣṇu. Thus although Lord Viṣṇu is the Supreme Personality of Godhead, He offered His respects to Kaśyapa Muni. Similarly, when Lord Kṛṣṇa was a child He used to offer His respectful obeisances to His mother and father, Nanda and Yaśodā. Also, at the Battle of Kurukṣetra, Lord Kṛṣṇa touched the feet of Mahārāja Yudhiṣṭhira because the King was His elder. It appears, then, that the Personality of Godhead, Lord Śiva and other devotees, in spite of their being situated in exalted positions, instructed by practical example how to offer obeisances to their superiors. Lord Śiva offered his respectful obeisances to Brahmā because Brahmā was his father, just as Kaśyapa Muni was the father of Vāmana.