Epistle to Diognetus

If you also desire [to possess] this faith, you likewise shall receive first of all the knowledge of the Father. For God has loved mankind, on whose account He made the world, to whom He rendered subject all the things that are in it, to whom He gave reason and understanding, to whom alone He imparted the privilege of looking upwards to Himself, whom He formed after His own image, to whom He sent His only-begotten Son, to whom He has promised a kingdom in heaven, and will give it to those who have loved Him.

And when you have attained this knowledge, with what joy do you think you will be filled? Or, how will you love Him who has first so loved you? And if you love Him, you will be an imitator of His kindness. And do not wonder that a man may become an imitator of God. He can, if he is willing. For it is not by ruling over his neighbours, or by seeking to hold the supremacy over those that are weaker, or by being rich, and showing violence towards those that are inferior, that happiness is found; nor can any one by these things become an imitator of God.

But these things do not at all constitute His majesty. On the contrary he who takes upon himself the burden of his neighbour; he who, in whatsoever respect he may be superior, is ready to benefit another who is deficient; he who, whatsoever things he has received from God, by distributing these to the needy, becomes a god to those who receive [his benefits]: he is an imitator of God. Then you shall see, while still on earth, that God in the heavens rules over [the universe]; then you shall begin to speak the mysteries of God; then shall you both love and admire those that suffer punishment because they will not deny God; then shall you condemn the deceit and error of the world when you shall know what it is to live truly in heaven, when you shall despise that which is here esteemed to be death, when you shall fear what is truly death, which is reserved for those who shall be condemned to the eternal fire, which shall afflict those even to the end that are committed to it.

Then shall you admire those who for righteousness' sake endure the fire that is but for a moment, and shall count them happy when you shall know [the nature of] that fire.