Śatapatha Brāhmaṇa ("of a hundred paths") 11.6.2.2

11.6.2.2

sa hovāca śvetaketurāruṇeyo gharmāveva samrāḍahamajasrau yaśasā viṣyandamānāvanyo'nyasminjuhomīti kathaṃ tadityādityo vai gharmastaṃ sāyamagnau juhomyagnirvai gharmastam prātarāditye juhomīti kiṃ sa bhavati ya evaṃ juhotyajasra eva śriyā yaśasā bhavatyetayośca devatayoḥ sāyujyaṃ salokatāṃ jayatīti

Svetaketu Âruneya replied, 'O great king, I make offering, in one another, to two heats, never-failing and overflowing with glory.'--'How is that?' asked the king.--'Well, Âditya (the sun) is heat: to him I make offering in Agni in the evening; and Agni, indeed, is heat: to him I make offering in the morning in Âditya.'--'What becomes of him who offers in this way?' asked the king.--'He verily becomes never-failing in prosperity and glory, and attains to 'the fellowship of those two deities, and to an abode in their world.'