A. The happiness in heaven consists in seeing the beauty of God, in knowing Him as He is, and in having every desire fully satisfied.

Q. 1397. What does St. Paul say of heaven?

A. St. Paul says of heaven, “That eye hath not seen, nor ear heard, neither hath it entered into the heart of man what things God hath prepared for them that love Him.” (I. Cor. ii., 9.)

Q. 1398. Are the rewards in heaven and the punishments in hell the same for all who enter into either of these states?

A. The rewards of heaven and the punishments in hell are not the same for all who enter into either of these states, because each one’s reward or punishment is in proportion to the amount of good or evil he has done in this world. But as heaven and hell are everlasting, each one will enjoy his reward or suffer his punishment forever.

Q. 1399. What words should we bear always in mind?

A. We should bear always in mind these words of our Lord and Saviour Jesus Christ: “What doth it profit a man if he gain the whole world and suffer the loss of his own soul, or what exchange shall a man give for his soul? For the Son of man shall come in the glory of His Father with His angels; and then will He render to every man according to his works.”

Q. 1400. Name some of the more essential religious truths we must know and believe.

A. Some of the more essential religious truths we must know and believe are: (1) That there is but one God, and He will reward the good and punish    the wicked. (2) That in God there are three Divine Persons: the Father, the Son, and    the Holy Ghost, and these Divine Persons are called the Blessed    Trinity. (3) That Jesus Christ, the Second Person of the Blessed Trinity, became    man and died for our redemption. (4) That the grace of God is necessary for our salvation. (5) That the human soul is immortal.  (Source: Baltimore Catechism #3 / Lesson ThirtY-SeventH. on The Last Judgment And The ResurrectioN, helL, purgatorY, and HeaveN.
Q. 1371. when Will Christ Judge Us?)