Bhagavad Geeta Chapter 9 - The Royal Secret
16. I am the kratu; I am the sacrifice; I am the offering (food) to pitrs (ancestors); I am the medicinal herb and all plants; I am the mantra; I am also the clarified butter; I am the fire; I am the oblation.
17. I am the father of this world, the mother, the sustainer and the grandsire; the (one) thing to be known, the purifier, (the syllable) Om, and also the Rk, the Sama and the Yjus also.