Apart from the preaching by Shri Krishna via Chapter 2, I personally believe in the Shloka 22 of Chapter 9 of Shrimad Bhagwadgita reading, “अनन्याश्चिन्तयन्तो माँ ये जनाः पर्युपासते।
तेषां नित्याभियुक्तानाम् योगक्षेमं वहाम्यहम्॥