Bhagavad Gita: Chapter 2, Verse 12

न त्वेवाहं जातु नासं न त्वं नेमे जनाधिपाः ।
न चैव नभविष्यामः सर्वे वयमतः परम् ॥ २-१२ ॥

na tv evāhaṁ jātu nāsaṁ na tvaṁ neme janādhipāḥ
na caiva na bhaviṣyāmaḥ sarve vayam ataḥ param 2.12

Never was there a time when I did not exist, nor you, nor all these rulers of men; nor in the future shall any of us cease to be.