A recent comment made me want to say more about aids and additions. To liken church buildings (because they aren't mentioned in Scripture) to instrumental music (IM) in Christian worship (because it is not in Scripture) is a popular thing to do. But such a suggestion is like mixing apples and oranges. IM is like adding a fourth floor to the ark, when only three floors are specified. Church buildings are like the tools necessary to build the ark. One violates silence, while the other does not. Why? Because when instructions are specific, they should be fulfilled specifically; and when instructions are generic, they can be fulfilled by the use of the most expedient means.
We might use another illustration. Neither a tray nor a roast lamb was mentioned in the instructions for the Lord's supper. But adding roast lamb to the Supper is a violation of it, while putting the bread on a tray is expedient.
There is no mention of a baptistery in Scripture, but there is no violation of Scripture to use one. It is an expedient in the fulfillment of the instructions to baptize and to be baptized. But to add another mode of baptism (you can be immersed or sprinkled) is a violation of the specifics of the word baptism.
In generic instructions, God grants permission for expedients (the means to do what He has instructed); but when God gives specific instructions, the addition of other things is a violation of God's will. That is why the altar of Ahaz was so sinful and why Hezekiah took it away when he cleansed the temple.