न ह वा अस्मा उदेति न निम्लोचति सकृद्दिवा हैवास्मै भवति य एतामेवं ब्रह्मोपनिषदं वेद ॥ ३.११.३ ॥
na ha vā asmā udeti na nimlocati sakṛddivā haivāsmai bhavati ya etāmevaṃ brahmopaniṣadaṃ veda || 3.11.3 ||
3. For him who knows the secret teachings of Brahman there is no sunrise or sunset [or day or night]. For him there is always day [i.e., light].
Na, not; ha vai asmai, so far as he is concerned; udeti, does [the sun] rise; na nimlocati, nor does it set; asmai, for him; sakṛt divā ha eva bhavati, there is always day [i.e., light]; yaḥ, he who; etām, this; evam, in this way; brahmopaniṣadam, the secret teachings about Brahman; veda, knows.
Earlier it was described how Brahman manifests itself in various forms—as a crossbeam, a honeycomb, etc., or as various gods enjoying various nectars. If you understand the underlying meaning of such manifestations, you then attain the knowledge of Brahman. To you then there is no day or night. You are like the sun—self-luminous. You are, in fact, one with Brahman—always the same, eternal, infinite.