Yadeva vidyayeti hi IV.4.18 (495)

Because the text "whatever he does with knowledge" intimates this.

Yadeva: whatever; Vidyaya: with knowledge; Iti: thus, this, so; Hi: because.

Nitya Karmas (regular obligatory works) which help the origination of knowledge are of two kinds, viz., those combined with meditations and those unaccompanied by knowledge or meditations.

The Purvapakshin maintains that work combined with meditations helps the origination of knowledge as it is superior to work done without meditation.

The present Sutra refutes it and says that in the statement "That alone which is performed with knowledge becomes more powerful" (Chh. Up. I.1.10) the comparative degree indicates that works done without knowledge, not combined with meditations are not altogether useless, though the other class is more powerful.

Even ordinary Agnihotra has Virya (power) but Agnihotra confirmed by Vidya (Upasana) is more potent (Viryavattara). Agnihotra if accompanied by knowledge possesses a greater capability of originating knowledge and, therefore, is of superior causal efficiency with regard to the realisation of the self, while the same works if devoid of knowledge possess no such superiority.