Avodah Zarah 14 - Devotion to Idols
However, selling a large bundle of these items is allowed. It can be assumed that the buyer is a merchant who will be reselling them at a profit, and the "stumbling block" prohibition does not go that far.
If an idol worshipper asks for other items, specifying that they are for idol worship, it is prohibited to sell them to him. One cannot rationalize that this man is simply so devoted to idol worship that he expects all others to be as devoted and sell to him at a discount.
The tractate Avodah Zarah of our father Abraham was comprised of 400 chapters. We have only five, and we encounter difficulties even with these, since we are not certain which cedar trees are meant above.
Art: Cedars on the Shore Near Atlantic City by William Trost Richards
