成唯識論述記 4.393

4.393

述曰：下初受生一剎那位，前生曾習第六意識亦應現起。即生得善，或勤煩惱久習工巧等。

The Commentary states: Below, at the single moment of initial birth, the sixth mental consciousness previously practiced in former lives should also become present. That is, innate good, or persistent afflictions, long-practiced crafts, and the like.