Srimad-Bhagavatam: Canto 5 - Chapter 1 - Verse 6
Sanskrit:
यावद्दक्षिणायनमहानि वर्धन्ते यावदुदगयनं रात्रय: ॥ ६ ॥
ITRANS:
yāvad dakṣiṇāyanam ahāni vardhante yāvad udagayanaṁ rātrayaḥ.
Translation:
Until the sun travels to the south the days grow longer, and until it travels to the north the nights grow longer.