Chapter XXXVII. Whom to Know is Life Eternal.
But if you art thankful, O man, understanding that God is your benefactor in all things, you may even be immortal, the things that are made for you having continuance through your gratitude. And now you are able to become incorruptible, if you acknowledge Him whom you did not know, if you love Him whom you forsook, if you pray to Him alone who is able to punish or to save your body and soul. Wherefore, before all things, consider that no one shares His rule, no one has a name in common with Him—that is, is called God. For He alone is both called and is God. Nor is it lawful to think that there is any other, or to call any other by that name. And if any one should dare do so, eternal punishment of soul is his.
Source: Clementine Homilies (New Advent)