3 In this love, then, all our holy fathers, patriarchs, prophets, and apostles pleased God. In this all true martyrs contended against the devil even to the shedding of blood, and because in them it neither waxed cold nor failed, they became conquerors. In this all true believers daily make progress, seeking to acquire not an earthly kingdom, but the kingdom of heaven; not a temporal, but an eternal inheritance; not gold and silver, but the incorruptible riches of the angels; not the good things of this life, which are enjoyed with trembling, and which no one can take with him when he dies, but the vision of God, whose grace and power of imparting felicity transcend all beauty of form in bodies not only on earth but also in heaven, transcend all spiritual loveliness in men, however just and holy, transcend all the glory of the angels and powers of the world above, transcend not only all that language can express, but all that thought can imagine concerning Him.
And let us not despair of the fulfilment of such a great promise because it is exceeding great, but rather believe that we shall receive it because He who has promised it is exceeding great, as the blessed Apostle John says: “Now are we the sons of God; and it does not yet appear what we shall be: but we know that, when He shall appear, we shall be like Him; for we shall see Him as He is.”
Source: Letters (New Advent)