Bhagavad Gita Chapter 9, Verse 19

तपाम्यहमहं वर्षं निगृह्णाम्युत्सृजामि च | अमृतं चैव मृत्युश्च सदसच्चाहमर्जुन ||

tapāmy aham ahaṁ varṣaṁ nigṛhṇāmy utsṛjāmi ca amṛtaṁ caiva mṛtyuś ca sad asac cāham arjuna

I give heat, and I withhold and send forth the rain. I am immortality as well as death, O Arjuna. I am being and non-being.

Krishna reveals His power over nature and existence: 'Tapāmy aham ahaṁ varṣaṁ nigṛhṇāmi utsṛjāmi ca'—I give (tapāmi) heat (aham), and I withhold (nigṛhṇāmi) and send forth (utsṛjāmi) the rain (varṣam). 'Amṛtaṁ caiva mṛtyuś ca sad asac cāham arjuna'—I am (aham) immortality (amṛtam) as well as (ca eva) death (mṛtyuḥ), and (ca) being (sat) and non-being (asat), O Arjuna. This reveals the Supreme's power: He controls nature—heat and rain. He is both immortality and death—the opposites. He is both being and non-being—existence and non-existence. This is the Supreme's completeness: He is everything—all opposites, all contradictions. Nothing is outside Him—He is all possibilities. This completes the teaching about the Supreme being everything: He controls nature, He is all opposites, He is everything.