SB 6.7.23
maghavan dvisatah pasya
praksinan gurv-atikramat
sampraty upacitan bhuyah
kavyam aradhya bhaktitah
adadiran nilayanam
mamapi bhrgu-devatah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O Indra, your enemies, the demons, were extremely weak because of their disrespect toward Sukracarya, but since they have now worshiped Sukracarya with great devotion, they have again become powerful. By their devotion to Sukracarya, they have increased their strength so much that now they are even able to easily seize my abode from me.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Lord Brahma wanted to point out to the demigods that by the strength of the guru one can become most powerful within this world, and by the displeasure of the guru one can lose everything. This is confirmed by the song of Visvanatha Cakravarti Thakura:
yasya prasadad bhagavat-prasado
yasyaprasadan na gatih kuto ’pi
“By the mercy of the spiritual master one is benedicted by the mercy of Krsna. Without the grace of the spiritual master, one cannot make any advancement.” Although the demons are insignificant in comparison to Lord Brahma, because of the strength of their guru they were so powerful that they could even seize Brahmaloka from Lord Brahma. We therefore pray to the spiritual master:
mukam karoti vacalam
pangum langhayate girim
yat-krpa tam aham vande
sri-gurum dina-taranam
(Madhya 17.80)
By the mercy of the guru, even a dumb man can become the greatest orator, and even a lame man can cross mountains. As advised by Lord Brahma, one should remember this sastric injunction if one desires success in his life.