Yoga teachers, during Buddha’s time, claimed that they represented the culmination of a spiritual life. But Buddha was wary of affirmations. He likewise did not accept the Brahman scriptures as spiritual truth.
But Buddha’s dismissing of other teachings should not be misunderstood. Knowledge does not come from hearsay nor tradition, he said, but rather from that which you “know for yourselves.”
There are many possible kinds of knowledge, said the Buddha, but only those in your immediate experience are relevant. “That which you assert, must be that which you have realised, seen, and known for yourself.”
(source: no. 3; pages 4, 35-38)