chañchalaṁ hi manaḥ kṛiṣhṇa pramāthi balavad dṛiḍham
tasyāhaṁ nigrahaṁ manye vāyor iva su-duṣhkaram||34||

Meaning : O Krishna, the mind is indeed restless, powerful, and difficult to control. I consider restraining it to be as hard as controlling the wind.