Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 22
Sanskrit:
सन्तन्वन्त: प्रजातन्तून् सुखं दु:खं भवाभवौ ।प्राप्तं प्राप्तं च सेवन्तो मच्चित्ता विचरिष्यथ ॥ २२ ॥
ITRANS:
santanvantaḥ prajā-tantūnsukhaṁ duḥkhaṁ bhavābhavauprāptaṁ prāptaṁ ca sevantomac-cittā vicariṣyatha
Translation:
As you live your lives, begetting generations of progeny and encountering happiness and distress, birth and death, always keep your minds fixed on Me.