Bodhidharma is talking about truth with a student.

Student: I heard that Buddha drank three bucketfuls and six bowlfuls of milk before he attained Buddhahood. Why do you now say, ‘complete liberation can be attained by watching the mind?’

Bodhidharma: The milk Buddha drank is not ordinary, impure milk, rather milk of the immaculate truth-as-it-is. Three bucketfuls means three immaculate precepts. Six bowlfuls means six paramitas; Buddha attained the Tao by drinking this immaculate truth-milk.

If one says rather, ‘Buddha drank the milk which comes from the carnal knowledge complicated by the dirty and soured milk’, this is actually humiliating the Buddha.

A sutra says;

This ox is not different from the luminous omnipresent, Buddha; with great love and compassion, it has pity for all indigent-beings. The immaculate Dharma-Body produced the sublime truth-milk of the three immaculate precepts and six perfections and nursed all who wished to attain complete liberation. Not just Buddha himself, but any who drink this milk will attain the highest, right and true Tao.