For some of us, the universe is not only a multitude of physical phenomena, but also a unity of which each of us is a part. The Upanishads speak of Brahman, the ultimate power sustaining the cosmos, and Atman, the internal spiritual power of the individual. In a divine equation of unspeakable sublimity, they determine that Brahman and Atman are one. Some Hindus spend the later part of their life in meditation of this cosmic mystery. Some Western philosophers also speak of a cosmic unity including Pythagoras, Plotinus, and Spinoza. Here self-mastery and relationship with the ultimate intersect in an ethical absolute.
Still others believe that there is a divine being separate from or superadded to the cosmos. Most who believe in a divine being do so as practitioners of a particular religion, such as Christianity or Islam, with recognized sacred texts. In that case the sacred text and experts such as priests or clerics typically provide guidance on relationship with the divine. This site cannot address in detail those authorities, but I urge those readers to read carefully the texts, reflect deeply on the meanings, and avoid the error (sin) of misinterpretation. A divine creator it seems to me would judge harshly the destruction of His creation or the taking of life in His name. It also seems unlikely that a divine creator of man would infuse in us reasoning power like that thoughtfully used by traditional philosophers that errs greatly in the ethics outlined above.
For the religious, there is another key method of relationship with the divine, discussed in detail by Thomas Merton in his book, The Inner Experience.1 Merton layers on top of classic Eastern meditation a higher level he calls contemplation, man’s ability to experience the divine in mystical union. Sufiism is the Islamic version of this union.
In summary, no matter what concept you possess on ultimate reality, there is an ethical correlate. It seems to me that at a minimum everyone should embrace a scientifically supported cosmic ethic through respect of nature and desire to appreciate, understand, and learn about the universe. For others there will be religious obligations and perhaps a desire to probe deeper by means of meditation and contemplation.
1Merton, Thomas, The Inner Experience. HarperSanFrancisco, 2003. ISBN 0-06-059362-8. Chapter 2, pages 7-18.