Heaven is a city on a hill, hence we cannot coast into it; we have to climb. Those who are too lazy to mount can miss its capture as well as the evil who refuse to seek it. Let no one think he can be totally indifferent to God in this life and suddenly develop a capacity for Him at the moment of death.
Where will the capacity of Heaven come from if we have neglected it on earth? A man cannot suddenly walk into a lecture room on higher mathematics and be thrilled by its equations if all during life he neglected to develop a taste for mathematics. A heaven of poets would be hell to those who never learned to love poetry. And a heaven of Divine Truth, Righteousness, and Justice would be a hell to those who never studiously cultivated those virtues here below.
—from Victory Over Vice by Venerable Fulton Sheen, Ch. 6 – The Sixth Word: Sloth