Bhagavad Gita 4.7
यदा यदा हि धर्मस्य ग्लानिर्भवति भारत।
अभ्युत्थानमधर्मस्य तदाऽऽत्मानं सृजाम्यहम्।।4.7।।
Yada yada hi dharmasya glanirbhavati bharata
Abhyutthanamadharmasya tadatmanam srijamyaham
Simple meaning, written by AIWhenever righteousness declines and unrighteousness rises, He creates Himself again.