11 But let us “not love the world, neither the things that are in the world. For the things that are in the world, are the lust of the flesh, and the lust of the eyes, and the pride of life.” These three are they: lest haply any man say, “The things that are in the world, God made: i.e. heaven and earth, the sea: the sun, the moon, the stars, all the garniture of the heavens. What is the garniture of the sea? All creeping things. What of the earth? animals, trees, flying creatures.
These are 'in the world,' God made them. Why then am I not to love what God has made?” Let the Spirit of God be in you, that you may see that all these things are good: but woe to you if you love the things made, and forsake the Maker of them! Fair are they to you: but how much fairer He that formed them! Mark well, beloved. For by similitudes you may be instructed: lest Satan steal upon you, saying what he is wont to say, Take your enjoyment in the creature of God; wherefore made He those things but for your enjoyment?
And men drink themselves drunken, and perish, and forget their own Creator: while not temperately but lustfully they use the things created, the Creator is despised. Of such says the apostle: “They worshipped and served the creature rather than the Creator, Who is blessed for ever.” God does not forbid you to love these things, howbeit, not to set your affections upon them for blessedness, but to approve and praise them to this end, that you may love your Creator. In the same manner, my brethren, as if a bridegroom should make a ring for his bride, and she having received the ring, should love it more than she loves the bridegroom who made the ring for her: would not her soul be found guilty of adultery in the very gift of the bridegroom, albeit she did but love what the bridegroom gave her?
By all means let her love what the bridegroom gave: yet should she say, “This ring is enough for me, I do not wish to see his face now:” what sort of woman would she be? Who would not detest such folly? Who not pronounce her guilty of an adulterous mind? You love gold in place of the man, lovest a ring in place of the bridegroom: if this be in you, that you love a ring in place of your bridegroom, and hast no wish to see your bridegroom; that he has given you an earnest, serves not to pledge you to him, but to turn away your heart from him!
For this the bridegroom gives earnest, that in his earnest he may himself be loved. Well then, God gave you all these things: love Him that made them. There is more that He would fain give you, that is, His very Self that made these things. But if you love these— what though God made them— and neglect the Creator and love the world; shall not your love be accounted adulterous?
Source: Homilies on the First Epistle of John (New Advent)