Brihadaranyaka Upanishad 2.1.5

2.1.5

sahovāca gārgyo ya evāyamākāśe puruṣa etamevāhaṃ brahmopāsa iti sa hovācājātaśatrurmā maitasminsaṃvadiṣṭhāḥ pūrṇamapravartīti vā ahametamupāsa iti sa ya etamevamupāste pūryate prajayā paśubhirnāsyāsmāllokātprajodvartate

Gârgya said: 'The person that is in the ether (and in the ether of the heart), that I adore as Brahman.' Agâtasatru said to him: 'No, no! Do not speak to me on this. I adore him as what is full, and quiescent.' Whoso adores him thus, becomes filled with offspring and cattle, and his offspring does not cease from this world.