Śrīmad-Bhāgavatam · Text 11.21.7
Who is speaking and story frame
देशकालादिभावानां वस्तूनां मम सत्तम ।
गुणदोषौ विधीयेते नियमार्थं हि कर्मणाम् ॥ ७ ॥
deśa-kālādi-bhāvānāṁ
vastūnāṁ mama sattama
guṇa-doṣau vidhīyete
niyamārthaṁ hi karmaṇām
O saintly Uddhava, in order to restrict materialistic activities, I have established that which is proper and improper among all material things, including time, space and all physical objects.
Read the purport on Vedabase.ioFrom Canto 10, chapter 14 onward, the translation and purports were completed by Śrīla Prabhupāda's disciples after his departure, and published by the Bhaktivedanta Book Trust.