Even a little of this practice (Karma Yoga) protects one from the great terror, there is no loss or diminution.
Body undergoes changes but soul inside doesn't and we do not change, therefore consciousness means pains and pleasures of the body.
The constitutional duty of every soul is to serve krsna. When we say soul never dies, but body does. It means soul takes another body.
Mourning for what is not worthy of grief and lamentation. A thing which is not in our control it is prudent not to lament on that.
So when we become very serious in a dangerous position, as if we are lost, but Kṛṣṇa smiles. You see? Sometimes we think... This is called illusion.
The reason for material problems is our very material existence only. As Lord Rishabadev says 'Actually the living entity should not have taken on a material body'.
Disciple Arjuna surrenders to Krsna, one who comes under the authorized Disciplic Succession, achieves the real goal of life