Srimad Bhagavatam Canto 06, Chapter 07, Text 21

SB 6.7.21

aho bata sura-srestha
 hy abhadram vah krtam mahat
brahmistham brahmanam dantam
 aisvaryan nabhyanandata
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Lord Brahma said: O best of the demigods, unfortunately, because of madness resulting from your material opulence, you failed to receive Brhaspati properly when he came to your assembly. Because he is aware of the Supreme Brahman and fully in control of his senses, he is the best of the brahmanas. Therefore it is very astonishing that you have acted impudently toward him.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Lord Brahma recognized the brahminical qualifications of Brhaspati, who was the spiritual master of the demigods because of his awareness of the Supreme Brahman. Brhaspati was very much in control of his senses and mind, and therefore he was a most qualified brahmana. Lord Brahma chastised the demigods for not properly respecting this brahmana, who was their guru. Lord Brahma wanted to impress upon the demigods that one’s guru should not be disrespected under any circumstances. When Brhaspati entered the assembly of the demigods, they and their king, Indra, took him for granted. Since he came every day, they thought, they did not need to show him special respect. As it is said, familiarity breeds contempt. Being very much displeased, Brhaspati immediately left Indra’s palace. Thus all the demigods, headed by Indra, became offenders at the lotus feet of Brhaspati, and Lord Brahma, being aware of this, condemned their neglect. In a song we sing every day, Narottama dasa Thakura says, caksu-dana dila yei, janme janme prabhu sei: the guru gives spiritual insight to the disciple, and therefore the guru should be considered his master, life after life. Under no circumstances should the guru be disrespected, but the demigods, being puffed up by their material possessions, were disrespectful to their guru. Therefore Srimad-Bhagavatam (11.17.27) advises, acaryam mam vijaniyan navamanyeta karhicit/ na martya-buddhyasuyeta: the acarya should always be offered respectful obeisances; one should never envy the acarya, considering him an ordinary human being.
Srimad Bhagavatam Canto 06, Chapter 07, Text 20
Srimad Bhagavatam Canto 06, Chapter 07, Text 22