Those who are not saved always are taking care of those things that do not profit or benefit them in any way. So what kind of excuse is there for a Christian who withdraws from the assembly of the church? Such a person does not even imitate the Gentiles but by reason of his absence grows indifferent and careless. He stands aloof and does evil. The Lord said, … You have not walked in my statutes or kept my ordinances, and have not even acted according to the rules of the nations that are all around you, “you were more corrupt than they in all your ways.” How, then, shall the indifferent excuse himself, since he has no zeal for the assembly of the church? If anyone takes the occasion of worldly business to withdraw, let him know this: the trades of the faithful are called works of surplus, for their true work is religion. Pursue your trades, therefore, as a work of surplus, for your sustenance, but let your true work be religion.
This alone among all evils is without comparison. This is a new act of shamelessness in life. “Go over to the islands of Kittim and see,” the Lord says. “Send to Kedar and consider carefully whether anything like this has ever been done—if a nation has changed its gods? (Yet they are not gods at all.).” But the virgin “has changed her glory,” and her glory is in her shame.
For since you are not persuaded by the Scriptures, I am compelled to shame you by those who are outside your company. God also did this to the Jews when he said, “Go to the Isles of Kittim and send to Kedar and find out if the nations will change their gods which are no gods.”
God actually permitted erroneous and unworthy opinions of himself to prevail—opinions such as that he was formerly a body and that he was visible.… For he nowhere considers his own dignity but always what will be profitable to us.… Even in reproving he stoops down, as when he speaks by the prophet, “Has a nation changed their gods?” And in every part of Scripture there are instances of his humility both in words and actions.
The same erroneous notion by which they used to worship devils formed in the figure of people they use even now in thinking that the incomprehensible and ineffable glory of the true Deity should be worshiped under the limitations of some figure. They think they are unable to grasp and hold anything if they do not have some image set before them that they can continually address while they are at their devotion and that they can carry about in their mind and have always fixed before their eyes.… Jeremiah also says, “My people have changed their glory for an idol.”
(Vers. 10, 11.) Go to the islands of Kittim, and see: and send to Kedar, and consider carefully, and see if such a thing has happened: if a nation has changed its gods (or its own gods). And certainly they are not gods: but my people have changed their glory into an idol (or something that will not profit them). He makes a comparison of that which is incomparable, and gives the true God to liars. Go, he says, to the islands of Kittim: which we should understand as either Italy or the Western lands: because the island of Cyprus, which is called by this name, is near the land of Judah. Of which both Zeno and the leader of the Stoics were. But the region of Cedar is one of solitude and of the Ismaelites, who are now called the Saracens: against whom the prophecy of the very Prophet himself is covered in the farthest parts (infra ad cap. XLIX); and of whom David mentions, saying: I have dwelt with those who dwell in Cedar: my soul has traveled much (Psal. CXIX, 5). And the meaning is: Either go to the West, or send into the wilderness, and see if any nation has done what you have done. For they did not despise their gods, neither the wooden and stone ones, nor did they change them in comparison to gold, but following the ancient error, they held onto what they had received from their ancestors. And certainly this is true, since none of their gods exist, but rather they are man-made idols. But my people have exchanged the truth for a lie and have preferred an idol to me, which will not be able to help them in times of need. We can also say this against those who pursue vices with more zeal than virtues, whom the Apostle warns, saying: I speak as a human, because of the weakness of your minds. Just as you presented your members as servants to impurity and lawlessness leading to more lawlessness, so now present your members as servants to righteousness leading to sanctification. (Romans 6:19).
[AD 230] Didascalia Apostolorum on Jeremiah 2:9-11