Yogācārabhūmi-śāstra, Volume 34 (75)

Original text: 当知此中。由观察作意。于一切修道。数数观察。已断未断。如所得道。而正修习。又于此中。云何名修自性。云何名修业。云何名修品类差别。谓由定地作意。于世出世善有为法。修习增长。无间所作。殷重所作。令心相续。会彼体性。如是名为修之自性。

Explanation: In the course of cultivating the path, because of the mental engagement of observation (investigative mental engagement), throughout the entire process of cultivating the path, one repeatedly and repeatedly examines which afflictions have already been eliminated and which have not yet been eliminated, and cultivates in accordance with the path one has attained, practicing correctly and in accord with reason. In the process of cultivating the four noble truths, what is called the nature of cultivation? What is called the function of cultivation? What are called the graded differences of cultivation? It means engaging the mind in meditation-ground mental engagement, cultivating and increasing wholesome conditioned dharmas, both worldly and transcendent, practicing without interruption, practicing with earnest diligence, making the mind continue unbroken, so that it abides continuously in wholesome dharmas, and the mind accords with the essential nature of the wholesome—this is called the nature of cultivation.