SB 4.29.66
mana eva manusyasya
purva-rupani samsati
bhavisyatas ca bhadram te
tathaiva na bhavisyatah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O King, all good fortune unto you! The mind is the cause of the living entity’s attaining a certain type of body in accordance with his association with material nature. According to one’s mental composition, one can understand what the living entity was in his past life as well as what kind of body he will have in the future. Thus the mind indicates the past and future bodies.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The mind is the index of information about one’s past and future lives. If a man is a devotee of the Lord, he cultivated devotional service in his previous life. Similarly, if one’s mind is criminal, he was criminal in his last life. In the same way, according to the mind, we can understand what will happen in a future life. In Bhagavad-gita (14.18) it is said:
urdhvam gacchanti sattva-stha
madhye tisthanti rajasah
jaghanya-guna-vrtti-stha
adho gacchanti tamasah
“Those situated in the mode of goodness gradually go upward to the higher planets; those in the mode of passion live on the earthly planets; and those in the mode of ignorance go down to the hellish worlds.”
If a person is in the mode of goodness, his mental activities will promote him to a higher planetary system. Similarly, if he has a low mentality, his future life will be most abominable. The lives of the living entity, in both the past and the future, are indicated by the mental condition. Narada Muni is herein offering the King blessings of all good fortune so that the King will not desire anything or make plans for sense gratification. The King was engaged in fruitive ritualistic ceremonies because he hoped to get a better life in the future. Narada Muni desired him to give up all mental concoctions. As explained before, all bodies in heavenly planets and hellish planets arise from mental concoctions, and the sufferings and enjoyments of material life are simply on the mental platform. They take place on the chariot of the mind (mano-ratha). It is therefore said:
yasyasti bhaktir bhagavaty akiñcana
sarvair gunais tatra samasate surah
harav abhaktasya kuto mahad-guna
mano-rathenasati dhavato bahih
“One who has unflinching devotion for the Personality of Godhead has all the good qualities of the demigods. But one who is not a devotee of the Lord has only material qualifications, that are of little value. This is because he is hovering on the mental plane and is certain to be attracted by the glaring material energy.” (Bhag. 5.18.12)
Unless one becomes a devotee of the Lord, or becomes fully Krsna conscious, he will certainly hover on the mental platform and be promoted and degraded in different types of bodies. All qualities that are considered good according to the material estimation actually have no value because these so-called good qualities will not save a person from the cycle of birth and death. The conclusion is that one should be without mental desire. Anyabhilasita-sunyam jñana-karmady-anavrtam: one should be fully free from material desires, philosophical speculation and fruitive activity. The best course for a human being is to favorably accept the transcendental devotional service of the Lord. That is the highest perfection of human life.