Why did Brahma ask the Buddha to teach after his enlightenment?

Following his enlightenment, the Buddha was initially hesitant to share his realization because he understood that his insights were so profound that they would be difficult for others to fathom.1

The god Brahma descended from his heaven to intervene, urging the Buddha to teach. Brahma pointed out that humans exist at different levels of spiritual development and that there were those who would benefit from the Buddha's guidance. Persuaded by this reasoning, the Buddha concluded that he should share his teachings, leading him to seek out his former companions to "set the wheel of the dharma in motion".1