Maitri (Maitrāyaṇīya) Upaniṣad 6.14

6.14

athānyātrapyuktam annaṃ vā asya sarvasya yoniḥ kālaścānnasya sūryo yoniḥ kālasya tasyaitadrūpaṃ yan nimeṣādikālātsambhṛtaṃ dvādaśātmakaṃ vatsarametasyāgneyamardhamardhaṃ vāruṇaṃ maghādyaṃ śraviṣṭhārdhamāgneyaṃ krameṇotkrameṇa sārpādyaṃ śraviṣṭhārdhāntaṃ saumyam tatraikaikamātmano navāṃśakaṃ sacārakavidham saukṣmyatvādetatpramāṇamanenaiva pramīyate hi kālaḥ na vinā pramāṇena prameyasyopalabdhiḥ prameyo'pi pramāṇatāṃ pṛthaktvādupaityātmasambodhanārthamityevaṃ hyāha | yāvatyo vai kālasya kalāstāvatīṣu caratyasau yaḥ kālaṃ brahmetyupāsīta kālastasyātidūramapasaratīti evaṃ hyāha
kālātsravanti bhūtāni kālādvṛddhiṃ prayānti ca |
kāle cāstaṃ niyacchanti kālo mūrtiramūrtimān ||

14. Now, it has elsewhere been said: ‘Food, verily, is the source of this whole world; and time, of food. The sun is the source of time.’

The form thereof is the year, which is composed of the moments and other durations of time, and which consists of twelve [months]. Half of it is sacred to Agni: half, to Varuṇa. From the asterism Maghā (the Sickle) to half of Śravishṭhā (the Drum) in the [sun’s southward] course is sacred to Agni. In its northward course, from Sarpa (the Serpent) to half of Śravishṭhā is sacred to Soma. Among these [asterisms] each month of Ātman [viewed as the year] includes nine quarters according to the corresponding course [of the sun through the asterisms]. On account of the subtilty [of time] this [course of