yajñasya ca vitanani
yogasya ca pathah prabho
naiskarmyasya ca sankhyasya
tantram va bhagavat-smrtam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Please also describe the expansions of different sacrifices and the paths of mystic powers, analytical study of knowledge, and devotional service, all with their respective regulations.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The word tantram is significant herein. Sometimes tantram is misunderstood to be the black spiritual science of materialistic persons engaged in sense gratification, but here tantram means the science of devotional service compiled by Srila Narada Muni. One can take advantage of such regulative explanations of the path of devotional service and make progressive advancement in the devotional service of the Lord. Sankhya philosophy is the basic principle of acquiring knowledge, as will be explained by the sage Maitreya. The Sankhya philosophy enunciated by Kapiladeva, the son of Devahuti, is the real source of knowledge about the Supreme Truth. Knowledge not based on the Sankhya philosophy is mental speculation and can yield no tangible profit.