俱舍論疏 23.56

23.56

論「頂初安足至未來十六」，明頂初入位也。初進異位故，行修唯法念。進位不簡行故，隨一行相修。「未來四及十六」者，許傍修故，四諦同故合說也。

The treatise says: "From the initial settling of the peak [summit stage] ... up to the sixteen in the future." This clarifies the initial entry into the summit stage. Because one is newly advancing into a different stage, cultivation of practice consists solely of the mindfulness of phenomena. Because when advancing through the stages the aspects are not selected, one cultivates according to any single aspect. As for "four and sixteen in the future," because lateral cultivation is admitted and because the four truths are the same, they are stated together.