SB 11.10.19

yadi prāptiṁ vighātaṁ ca
 jānanti sukha-duḥkhayoḥ
te ’py addhā na vidur yogaṁ
 mṛtyur na prabhaved yathā
Word for word: 
yadi — if; prāptim — achievement; vighātam — removal; ca — also; jānanti — they know; sukha — of happiness; duḥkhayoḥ — and of distress; te — they; api — still; addhā — directly; na — not; viduḥ — do know; yogam — the process; mṛtyuḥ — death; na — not; prabhavet — would exert its power; yathā — by which.
Translation: 
Even if people know how to achieve happiness and avoid unhappiness, they still do not know the process by which death will not be able to exert its power over them.
Purport: 

If the so-called intelligent materialists know the means of achieving happiness and destroying unhappiness, then they should deliver people from inevitable death. The scientists are busily working to solve this problem, but since they have completely failed, it is understood that they are not actually intelligent and that they do not know the means of achieving happiness and eliminating misery. It is most foolish to think that one can be happy with an ax hanging over one’s neck. Lord Kṛṣṇa says in Bhagavad-gītā, mṛtyuḥ sarva-haraś cāham: “I Myself come before you as death and take everything away.” We should not blindly ignore the disaster of material life, but should instead accept the Lord’s causeless mercy, which He so magnanimously offers in His incarnation as Caitanya Mahāprabhu. We should surrender to the lotus feet of Lord Caitanya, who offers the real means for achieving unqualified happiness: the chanting of the holy names of the Lord. This is the Lord’s desire, and it is in our own self-interest to take up this process.