妙法蓮華經文句 3.78

3.78

背色想生死煩惱境界在後故，觀寂滅涅槃所緣在前，故應作四解（云云）。

Because turning one's back on the realms of form, conceptualization, saṃsāra, and afflictions leaves them behind, the object of conditioning—the contemplation of tranquil extinction and nirvāṇa—is in front. Thus four explanations should be made (and so forth).