St. Thomas Aquinas

It is fitting that the end of all our desires, namely eternal life coincides with the words at the end of the creed, “Life everlasting. Amen.”  The first point about eternal life is that man is united with God. For God himself is the reward and end of all our labours: I am your protector and your supreme reward. This union consists in seeing perfectly: At present we see through a glass, darkly; but then we shall see face to face.  Next it consists in perfect praise, according to the words of the prophet: Joy and happiness will be found in it, thanksgiving and words of praise.  It also consists in the complete satisfaction of desire, for there the blessed will be given more than they wanted or hoped for. ... Again, eternal life consists of the joyous community of all the blessed, a community of supreme delight, since everyone will share all that is good with all the blessed. Everyone will love everyone else as himself, and therefore will rejoice in another’s good as in his own. So it follows that the happiness and joy of each grows in proportion to the joy of all.