大乘義章 13.76

13.76

次對諸禪辨定先後。如論中說「九想是其諸禪方便，先修九想折伏煩惱，然後入禪。」問曰：經中多先說禪、後說九想，今云何言九想是其趣禪方便？龍樹釋言「先讚諸禪令人愛樂，所樂禪定由九想成，故先行之（此六門竟）。」

Next, the sequence is determined in comparison to the various dhyānas. As it is said in the treatise: "The nine notions are the preliminary expedients for the various dhyānas; one first cultivates the nine notions to subdue the afflictions, and thereafter enters dhyāna." Question: In the sūtras, it is mostly spoken first of dhyāna and only afterward of the nine notions; why is it now said that the nine notions are the expedients for approaching dhyāna? Nāgārjuna explains: "First, the various dhyānas are praised to cause people to love and delight in them; the delightful dhyāna samādhi is accomplished through the nine notions, so one practices them first" (this concludes the sixth section).