This human life is meant for advancing on the path of liberation. That is called apavarga, freedom from entanglement. We are all entangled. Our acceptance of this material body means that we are already entangled. But we should not progress in the process of entanglement. That process is called karma. As long as the mind is absorbed in karma, we will have to accept a material body. At the time of death, our mind may be thinking, “Oh, I could not complete this work. Oh, I am dying! I have to do this. I have to do that.” This means that Kṛṣṇa will give us another chance to do it, and so we will have to accept another body. He will give us the chance: “All right. You could not do it. Now do it. Take this body.”
As long as we have even the slightest tinge of an idea of becoming happy materially in some way or other, we shall have to accept a material body. Nature is so kind that according to the way we want to enjoy this material world, she will give us a suitable body, under the direction of the Lord. Because the Lord is situated in everyone’s heart, He knows everything. Therefore, knowing that we still want something material, He will give us another material body: “Yes, take it.” Kṛṣṇa wants us to have full experience through which to understand that by material gain we shall never be happy. This is Kṛṣṇa’s desire.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Teachings of Queen Kunti”, Page 68
A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “The Science of Self-Realization”, Page 160