vedera - of the Vedic literature; nigūḍha - confidential; artha - meaning; bujhana - understanding; nā - not; haya - is; purāṇa-vākye - by the words of the Purāṇas; sei - that; artha - meaning; karaya - makes; niścaya - certain.

“The confidential meaning of the Vedas is not easily understood by common men; therefore that meaning is supplemented by the words of the Purāṇas.