Srimad-Bhagavatam: Canto 5 - Chapter 1 - Verse 3
Sanskrit:
स एष भगवानादिपुरुष एव साक्षान्नारायणो लोकानां स्वस्तय आत्मानं त्रयीमयं कर्मविशुद्धिनिमित्तं कविभिरपि च वेदेन विजिज्ञास्यमानो द्वादशधा विभज्य षट्सु वसन्तादिष्वृतुषु यथोपजोषमृतुगुणान् विदधाति ॥ ३ ॥
ITRANS:
sa eṣa bhagavān ādi-puruṣa eva sākṣān nārāyaṇo lokānāṁ svastaya ātmānaṁ trayīmayaṁ karma-viśuddhi-nimittaṁ kavibhir api ca vedena vijijñāsyamāno dvādaśadhā vibhajya ṣaṭsu vasantādiṣv ṛtuṣu yathopa-joṣam ṛtu-guṇān vidadhāti.
Translation:
The original cause of the cosmic manifestation is the Supreme Personality of Godhead, Nārāyaṇa. When great saintly persons, fully aware of the Vedic knowledge, offered prayers to the Supreme Person, He descended to this material world in the form of the sun to benefit all the planets and purify fruitive activities. He divided Himself into twelve parts and created seasonal forms, beginning with spring. In this way He created the seasonal qualities, such as heat, cold and so on.