SB 11.24.6
tebhyah samabhavat sutram
mahan sutrena samyutah
tato vikurvato jato
yo ’hankaro vimohanah
Translation:
From these modes arose the primeval sutra, along with the mahat-tattva. By the transformation of the mahat-tattva was generated the false ego, the cause of the living entities’ bewilderment.
Purport:
According to Srila Sridhara Svami, sutra is the first transformation of material nature that manifests the potency of activity, and it is accompanied by the mahat-tattva, which is endowed with the potency of knowledge. In the material world, one’s real knowledge is covered by fruitive activity and mental speculation. As one’s devotional service to the Lord slackens, these two tendencies grow automatically, just as the diminishing of light automatically brings an increase in darkness.