Athanasius of Alexandria

Now the so-called gods of the Greeks, unworthy of the name, are faithful neither in their essence nor in their promises, because they are not everywhere. The local deities amount to nothing over the course of time and undergo a natural extinction. For these reasons, the Word cries out against them, that "faith is not strong in them," that they are "waters that fail" and "there is no faith in them." But the God of all, who is indeed truly faithful, who is ever the same, says, "See now that I, even I am he," and "I change not." Therefore, his Son is "faithful," being ever the same and unchanging, deceiving neither in his essence nor in his promise, as is written by the apostle to the Thessalonians: "Faithful is he who calls you, who also will do it." For in doing what he promises, he is faithful to his words.