SB 1.3.25
जनिता विष्णुयशसो नाम्ना कल्किर्जगत्पतिः ॥ २५ ॥
janitā viṣṇu-yaśaso nāmnā kalkir jagat-patiḥ
Synonyms
atha — then; yuga-sandhyāyām — at the conjunction of the yugas [at the end of Kaliyuga (kaler ante)115]; rājasu — [when] the rulers; dasyu-prāyeṣu — [will] mostly have become plunderers [(caura-prāyeṣu), driven by immorality alone (kevalam adharma-bahuleṣu)116]; asau — He [the Puruṣa]; jagat-patiḥ — the guardian of the universe; janitā — will appear [(janiṣyate); (avatariṣyati);117 (prādurbhaviṣyati)118]; [for the purpose of vanquishing them (tad-vaddhārtham)119]; nāmnā — [as the avatāra] named; kalkiḥ — Kalki; viṣṇu-yaśasaḥ — from the brāhmaṇa known as Viṣṇuyaśā [(viṣṇu-yaśo brāhmaṇāt); as his son (putra-rūpeṇa)120].
Translation
Then, at the conjunction of the yugas, when the rulers will mostly have become plunderers, the guardian of the universe will appear as the avatāra named Kalki from the brāhmaṇa known as Viṣṇuyaśā.