। ॥ ३९१ ॥
In plain words
...wise teachers proclaim this consciousness to be Taijasa. Because its limiting adjunct is the luminous inner instrument, this is indeed Taijasa.
Close to the Sanskrit
...consciousness is Taijasa, thus proclaim the wise. By being [conditioned by] the limiting adjunct of the luminous inner instrument, this [is] Taijasa.