chandogya upnishad 1.2.24
1—2. The expounders of Brahman (i.e. the Vedas) ask: "Since the morning oblation belongs to the Vasus, the midday oblation to the Rudras and the third (i.e. evening) oblation to the Adityas and the Visve—devas, "Where, then, is the world of the sacrificer?" He who does not know this, how can he perform the sacrifice? Only he who knows should perform it.
3—4. Before beginning the morning chant, the sacrificer, sitting behind the Garhapatya Fire and facing the north, sings the Saman addressed to the Vasus: "O Fire! Open the door of the earth—world. Let us see thee, that we may rule this earth.
5—6. Then the sacrificer offers an oblation, reciting thus: "Adoration to Agni, who dwells in the earth—world! Secure this world for me, the sacrificer. That is the world for the sacrificer. "I, the sacrificer, will go thither when this life is over. Svaha!" Afterwards the sacrificer chants: "Cast away the bolt of the earth—world." Having said this, he rises. To him the Vasus offer the world connected with the morning oblation.
7—8. Before beginning the midday oblation, the sacrificer, sitting behind the Dakshina Fire and facing the north, sings the Saman addressed to the Rudras: "O Fire! Open the door of the sky—world. Let us see thee, that we may rule wide in the sky—world."
9—10. Then the sacrificer offers an oblation, reciting thus: "Adoration to Vayu, who dwells in the sky—world! Secure this world for me, the sacrificer. That is the world for the sacrificer. "I, the sacrificer, will go thither when this life is over. Svaha!" Afterwards the sacrificer chants: "Cast away the bolt of the sky—world." Having said this, he rises. To him the Rudras offer the world connected with the midday oblation.
11—13. Before beginning the third (i.e. evening) oblation, the sacrificer, sitting behind the Ahavaniya Fire and facing the north, sings the two Samans addressed to the Adityas and the Visve— devas: "O Fire! Open the door of the heaven—world. Let us see thee, that we may rule supreme in heaven." This is addressed to the Adityas. Next the Saman addressed to the Visve—devas: "O Fire! Open the door of the heaven—world. Let us see thee, that we may rule supreme in heaven."
14—15. Then the sacrificer offers an oblation, reciting thus: "Adoration to Adityas and the Visve—devas, who dwell in the heaven— world! Secure this world for me, the sacrificer. That is the world for the sacrificer. "I, the sacrificer, will go thither when this life is over. Svaha! Afterwards the sacrificer chants: "Cast away the bolt of the heaven—world." Having said this, he rises.
16. To him the Adityas and the Visve—devas offer the world connected with the third oblation. He (the sacrificer) who knows this knows the measure of the sacrifice, yea, he knows it.
16. To him the Adityas and the Visve—devas offer the world connected with the third oblation. He (the sacrificer) who knows this knows the measure of the sacrifice, yea, he knows it.