The nature of the mind is flickering and unsteady. However, one should always endeavor to control the mind from its wanderings and bring it back under the control of the higher self (atma).
Bhagavad Gita - Chapter 6 - Dhyana Yoga - The Yoga of Meditation
Supreme bliss comes to a yogi who subdues his passions, whose mind is calm, who is free of vice and who is always situated on the spiritual plane.
In this way, through the constant practice of yoga, a yogi who is devoid of material contamination can attain eternal bliss through contact with the Absolute.
One who is connected to the Supreme sees all things equally and perceives the Supreme in all living beings and all beings within the Supreme.
For one who sees Me in all things and sees everything within Me, I am never lost and they are never lost to Me.
That yogi who venerates Me, with the knowledge that I am situated in all living beings (as the Super Consciousness), abides in Me in all circumstances.
O Arjuna, one who regards with equanimity the happiness and distress of all others, as if it were their own, is considered the best of yogis.
Arjuna said: O Madhusudana, I cannot conceive of this system of yoga that You have described because by nature the mind is very unsteady.
The mind is erratic, disturbed, very powerful and stubborn. O Krishna, I think that to control it is as difficult as trying to control the wind.
Bhagavan Shri Krishna replied: O mighty-armed one, indeed the mind is unsteady and very difficult to control. However, it is possible to control the mind by practice and detachment, O son of Kunti.