Srimad Bhagavatam Canto 02, Chapter 08, Text 14

SB 2.8.14

yasmin karma-samavayo
yatha yenopagrhyate
gunanam guninam caiva
parinamam abhipsatam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Then again, kindly describe how the proportionate accumulation of the reactions resulting from the different modes of material nature act upon the desiring living being, promoting or degrading him among the different species of life, beginning from the demigods down to the most insignificant creatures.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
The actions and reactions of all works in the material modes of nature, either in the minute form or in the gigantic form, are accumulated, and thus the result of such accumulated actions and reactions of karma, or work, become manifested in the same proportion. How such actions and reactions take place, what the different procedures are, and in what proportion they act are all subject matters of Maharaja Pariksit’s inquiries from the great brahmana Sukadeva Gosvami.
Life in the higher planets, known as the abodes of the denizens of heaven, is obtained not by the strength of spacecraft (as is now being contemplated by the inexperienced scientists), but by works done in the mode of goodness.
Even on the very planet where we are now living, there are restrictions upon the entrance of foreigners into a country where the citizens are more prosperous. For example, the American government has many restrictions for the entrance of foreigners from less prosperous countries. The reason is that the Americans do not wish to share their prosperity with any foreigner who has not qualified himself as a citizen of America. Similarly, the same mentality is prevailing in every other planet where there are more intelligent living beings residing. The higher planetary living conditions are all in the mode of goodness, and anyone desiring to enter the higher planets like the moon, sun and Venus must qualify thoroughly by activity in complete goodness.
Maharaja Pariksit’s inquiries are on the basis of proportionate actions of goodness which qualify one in this planet to be promoted to the highest regions of the universe.
Even on this planet of our present residence, one cannot achieve a good position within the social order without being qualified with proportionate good work. One cannot forcibly sit on the chair of a high-court judge without being qualified for the post. Similarly, one cannot enter into the higher planetary systems without being qualified by good works in this life. Persons addicted to the habits of passion and ignorance have no chance of entering the higher planetary systems simply by an electronic mechanism.
According to the statement of the Bhagavad-gita (9.25), persons trying to qualify themselves for promotion to the higher, heavenly planets can go there; similarly, persons trying for the Pitrlokas can go there; similarly, persons trying to improve the conditions on this earth can also do that, and persons who are engaged in going back home, back to Godhead, can achieve that result. The various actions and reactions of work in the mode of goodness are generally known as pious work with devotional service, culture of knowledge with devotional service, mystic powers with devotional service and (at last) devotional service unmixed with any other varieties of goodness. This unmixed devotional service is transcendental and is called para bhakti. It alone can promote a person to the transcendental kingdom of God. Such a transcendental kingdom is not a myth, but is as factual as the moon. One must have transcendental qualities to understand the kingdom of God and God Himself.
Srimad Bhagavatam Canto 02, Chapter 08, Text 13
Srimad Bhagavatam Canto 02, Chapter 08, Text 15