There is story in the Puranas which help us understand the true power of the rishis of Sanatana Dharma. The story is associated with Sage Vishwamitra and Indra, the king of Devas (demigods).
Rishi Vishwamitra was performing intense penance to attain self realization. His penance was so powerful that it threatened the reign of present Indra, the king of heaven.
Indra, who constantly remained insecure, wanted to stop the penance of Sage Vishwamitra.
So, Indra came in the disguise of a sage and asked for food from Vishwamitra.
When Vishwamitra arrived with food, Indra told the sage that he was going to take bath and to keep the food warm till he returned.
Indra left to take bath and never returned.
He stayed away for years. But the food remained warm.
Indra was amazed that his food still remained warm Sage Vishwamitra.
Rishi Vishwamitra knew the power of Gayatri Mantra and used it to keep the food warm.
He put the pot of food on his head and recited the Gayatri mantra repeatedly.
Indra realized the power of Vishwamitra Rishi and returned back to sage and asked for pardon.