The previous verse set the body in position. Now Krishna describes what should be happening inside. The mind should be peaceful. Fear should be absent. The senses should be disciplined — brahmacharya here means control over all the senses, not merely celibacy in the narrow sense. With the mind restrained, the meditator turns attention toward Krishna.
The last word — matparah, 'holding Me as the highest' — adds a devotional dimension to what has been a practical meditation guide. The technique is yogic, but the destination is personal. Krishna is saying: use the method, but keep your eyes on Me.
Fear and restlessness are the two biggest obstacles in meditation. Fear of the unknown, fear of failure, fear of what the silence might reveal. Krishna names it directly and says: let it go. A fearless, calm mind is the only mind that can genuinely meditate.