God accordingly, in His kindness, condescends to mankind, not in any local sense, but through His providence; while the Son of God, not only (when on earth), but at all times, is with His own disciples, fulfilling the promise, “Lo, I am with you always, even to the end of the world.” And if a branch cannot bear fruit except it abide in the vine, it is evident that the disciples also of the Word, who are the rational branches of the Word's true vine, cannot produce the fruits of virtue unless they abide in the true vine, the Christ of God, who is with us locally here below upon the earth, and who is with those who cleave to Him in all parts of the world, and is also in all places with those who do not know Him.
Another is made manifest by that John who wrote the Gospel, when, speaking in the person of John the Baptist, he said, “There stands one among you whom you know not; He it is who comes after me.” And it is absurd, when He who fills heaven and earth, and who said, “Do I not fill heaven and earth? Says the Lord,” is with us, and near us (for I believe Him when He says, “I am a God near at hand, and not afar off, says the Lord”) to seek to pray to sun or moon, or one of the stars, whose influence does not reach the whole of the world. But, to use the very words of Celsus, let it be granted that “the sun, moon, and stars do foretell rain, and heat, and clouds, and thunders,” why, then, if they really do foretell such great things, ought we not rather to do homage to God, whose servant they are in uttering these predictions, and show reverence to Him rather than His prophets?
Let them predict, then, the approach of lightnings, and fruits, and all manner of productions, and let all such things be under their administration; yet we shall not on that account worship those who themselves offer worship, as we do not worship even Moses, and those prophets who came from God after him, and who predicted better things than rain, and heat, and clouds, and thunders, and lightnings, and fruits, and all sorts of productions visible to the senses. Nay, even if sun, and moon, and stars were able to prophesy better things than rain, not even then shall we worship them, but the Father of the prophecies which are in them, and the Word of God, their minister.
But grant that they are His heralds, and truly messengers of heaven, why, even then ought we not to worship the God whom they only proclaim and announce, rather than those who are the heralds and messengers?
Source: Against Celsus (New Advent)