From Manu Smriti:
12.95. All those traditions (smriti) and those despicable systems of philosophy, which are not based on the Veda, produce no reward after
death; for they are declared to be founded on Darkness.
12.96. All those (doctrines), differing from the (Veda), which spring up and (soon) perish, are worthless and false, because they are of