SB 4.1.62

vaitānike karmaṇi yan-
 nāmabhir brahma-vādibhiḥ
āgneyya iṣṭayo yajñe
 nirūpyante ’gnayas tu te
Word for word: 
vaitānike — offering of oblations; karmaṇi — the activity; yat — of the fire-gods; nāmabhiḥ — by the names; brahma-vādibhiḥ — by impersonalist brāhmaṇas; āgneyyaḥ — for Agni; iṣṭayaḥ — sacrifices; yajñe — in the sacrifice; nirūpyante — are the objective; agnayaḥ — the forty-nine fire-gods; tu — but; te — those.
Translation: 
These forty-nine fire-gods are the beneficiaries of the oblations offered in the Vedic sacrificial fire by impersonalist brāhmaṇas.
Purport: 

Impersonalists who perform Vedic fruitive sacrifices are attracted to the various fire-gods and offer oblations in their name. The forty-nine fire-gods are described herewith.