The Lord does not want any one of His innumerable sons (the living entities) to remain in the material world of threefold miseries to perpetually suffer the material pangs of birth, death, old age and disease. The demigods in the heavenly planets, and many devotees on this planet also, want to remain in the material world as devotees of the Lord and take advantage of material happiness. They do so at a risk of falling down to the lower status of existence, and this makes the Lord dissatisfied with them.
(Srimad Bhagavatam----3:9:12----purport).

The living entities, however, are actually eternal. They want an eternal home, an eternal residence, but because of accepting a temporal abode in the material world, they are naturally full of anxiety. In the spiritual sky the planets are called Vaikuṇṭha because the residents of these planets are free from all anxieties. For them there is no question of birth, death, old age and diseases, and therefore they are not anxious. On the other hand, the residents of the material planets are always afraid of birth, death, disease and old age, and therefore they are full of anxieties.
(Srimad Bhagavatam----3:15:13----purport).

Actually, it is impossible even for Lord Brahmā to give anyone the benediction of becoming immortal, but indirectly Hiraṇyakaśipu received the benediction that no one within this material world would be able to kill him. In other words, because he originally came from the abode of Vaikuṇṭha, he was not to be killed by anyone within this material world. The Lord desired to appear Himself to kill him. One may be very proud of his material advancement in knowledge, but he cannot be immune to the four principles of material existence, namely birth, death, old age and disease. It was the Lord's plan to teach people that even Hiraṇyakaśipu, who was so powerful and strongly built, could not live more than his destined duration of life.
(Srimad Bhagavatam----3:17:19----purport).

The spirit soul is actually sac-cid-ānanda (Bs. 5.1)—eternal, full of bliss and full of knowledge. Under the clutches of māyā, however, he suffers from continued birth, death, disease and old age. One has to be serious to cure this condition of material existence and transfer himself to Kṛṣṇa consciousness, for thus his long suffering may be mitigated without difficulty. In summary, the suffering of the conditioned soul is due to his attachment to material nature. This attachment should thus be transferred from matter to Kṛṣṇa.
(Srimad Bhagavatam----3:26:7----purport).

To take birth in a nice place or a high family does not mean that one avoids undergoing the material tribulations, the pangs of birth, death, old age and disease. A conditioned soul under the spell of material nature cannot understand that any action he performs for sense gratification is faulty and that only his activities in devotional service to the Lord can give him release from the reaction of faulty activities.
(Srimad Bhagavatam----3:27:3----purport).

In Bhagavad-gītā the Lord points out that a person who is serious about advancement in spiritual consciousness should always consider the four pangs of birth, death, disease and old age. The materialist advances in many ways, but he is unable to stop these four principles of suffering inherent in material existence.
(Srimad Bhagavatam----3:31:23----purport).

Śrī Caitanya Mahāprabhu has instructed that if from the very beginning we do not take care of unwanted grass in the paddy fields, the fertilizing agents or water will be used by them, and the paddy plants will dry up. The material desire for sense enjoyment is the cause of our falldown in this material world, and thus we suffer the threefold miseries and continuous birth, death, old age and disease. However, if we turn our desires toward the transcendental loving service of the Lord, our desires become purified. We cannot kill desires. We have to purify them of different designations.
(Srimad Bhagavatam----4:22:30----purport).

Regulated human civilization promotes dharma, artha, kāma and mokṣa. In human society there must be religion. Without religion, human society is only animal society. Economic development and sense gratification must be based on religious principles. When religion, economic development and sense gratification are adjusted, liberation from this material birth, death, old age and disease is assured. In the present age of Kali, however, there is no question of religion and liberation. People have taken interest only in economic development and sense gratification. Therefore, despite sufficient economic development all over the world, dealings in human society have become almost animalistic.
(Srimad Bhagavatam----4:22:36----purport).

Foolish materialistic persons do not know how they are being controlled and punished at every step by the laws of nature. They think they are very happy in the conditioned state of material life, not knowing the purpose of repeated birth, death, old age and disease. Therefore in Bhagavad-gītā (7.15) Lord Kṛṣṇa describes such materialistic persons as mūḍhas (rascals): na māṁ duṣkṛtino mūḍhāḥ prapadyante narādhamāḥ. These mūḍhas do not know that if they want to purify themselves, they must worship Lord Vāsudeva (Kṛṣṇa) by performing penances and austerities. This purification is the aim of human life.
(Srimad Bhagavatam----5:18:2----purport).

If one can somehow or other, by the grace of the Lord, understand the transcendental position of the Lord, one becomes eternal. This is further confirmed by the Lord Himself in Bhagavad-gītā (4.9):
janma karma ca me divyam
evaṁ yo vetti tattvataḥ
tyaktvā dehaṁ punar janma
naiti mām eti so 'rjuna
"One who knows the transcendental nature of My appearance and activities does not, upon leaving the body, take his birth again in this material world, but attains My eternal abode, O Arjuna." Simply by understanding the Supreme Lord, one goes beyond birth, death, old age and disease.
(Srimad Bhagavatam----6:4:29----purport).

The history of the world has factually proved that attempts to increase economic development for bodily comfort through the advancement of material civilization have done nothing to remedy the inevitability of birth, death, old age and disease. Everyone has knowledge of huge empires throughout the history of the world—the Roman Empire, the Moghul Empire, the British Empire and so on—but all the societies engaged in such economic development (sarve 'rtha-kāmāḥ) have been frustrated by the laws of nature through periodic wars, pestilence, famine and so on.
(Srimad Bhagavatam----7:7:39----purport).

The Supreme Personality of Godhead, the Supersoul, is present in everyone's heart, and as the living entity desires, the Lord gives him facilities with which to work according to his ambitions in different grades of bodies. The body is just like an instrument by which the living entity moves according to false desires for happiness and thus suffers the pangs of birth, death, old age and disease in different standards of life. Everyone begins his activities with some plan and ambition, but actually, from the beginning of one's plan to the end, one does not derive any happiness. On the contrary, as soon as one begins acting according to his plan, his life of distress immediately begins.
(Srimad Bhagavatam----7:7:42----purport).

A Vaiṣṇava can understand that nothing within this material world, not even that which is powerful, opulent or influential, can endure. At any time such things may be vanquished. And who can vanquish them? The Supreme Personality of Godhead. Therefore one should conclusively understand that no one is greater than the Supreme Great. Since the Supreme Great demands, sarva-dharmān parityajya mām ekaṁ śaraṇaṁ vraja (B.G.18:66), every intelligent man must agree to this proposal. One must surrender unto the Lord to be saved from the wheel of repeated birth, death, old age and disease.
(Srimad Bhagavatam----7:9:23----purport).

Because every one of us is a part of Kṛṣṇa, we have a very affectionate relationship with Him, but because we have forgotten our identities and are considering the body to be the self, we are afflicted by all the troubles of birth, death, old age and disease. This misconception in materialistic life continues unless and until one comes to understand his relationship with Kṛṣṇa.
(Srimad Bhagavatam----7:13:28----purport).

When one misuses the gift of the human form by unnecessarily indulging in the animal propensities of eating, sleeping, mating and defending and does not try to get out of the clutches of māyā, which subjects one to repeated birth, death, old age and disease, one is again punished by being forced to descend to the lower species and undergo evolution according to the laws of nature.
(Srimad Bhagavatam----7:14:5----purport).