SB 7.2.49
atha nityam anityam va
neha socanti tad-vidah
nanyatha sakyate kartum
sva-bhavah socatam iti
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Those who have full knowledge of self-realization, who know very well that the spirit soul is eternal whereas the body is perishable, are not overwhelmed by lamentation. But persons who lack knowledge of self-realization certainly lament. Therefore it is difficult to educate a person in illusion.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
According to the mimamsa philosophers, everything is eternal, nitya, and according to the Sankhya philosophers everything is mithya, or anitya — impermanent. Nonetheless, without real knowledge of atma, the soul, such philosophers must be bewildered and must continue to lament as sudras. Srila Sukadeva Gosvami therefore said to Pariksit Maharaja:
srotavyadini rajendra
nrnam santi sahasrasah
apasyatam atma-tattvam
grhesu grha-medhinam
“Those who are materially engrossed, being blind to knowledge of the ultimate truth, have many subjects for hearing in human society, O Emperor.” (Bhag. 2.1.2) For ordinary persons engaged in material activities there are many, many subject matters to understand because such persons do not understand self-realization. One must therefore be educated in self-realization so that under any circumstances in life he will remain steady in his vows.