הלכה אויף נחמיה 2:20

They would build a ramp from the Temple Mount to the Mount of [Olives] upon which they would remove the red heifer; and a ramp upon which they would remove the scapegoat. And both of them were made from the leftovers of the chamber. And likewise the sacrificial altar; the chamber; and the courtyards were made from the leftovers of the chamber. The aqueduct in Jerusalem; the wall of Jerusalem and all of its towers; and all of the needs of the city come from the leftovers of the chamber. [In a case of] an idolater that pledged money for these things or to do them for free: We do not accept it from him – even if he is a resident alien (who is not an idolater) – as it is stated (Ezra 4:3), "It is not for you and us to build, etc."; and it is [also] stated (Nehemiah 2:20), "and you have no portion, etc."

If a Gentile donated something to the Temple fund [for the Temple in Jerusalem], they may not accept [it] before the fact, but if they already took it from him, they may not return it to him. If it is something affixed, such as a beam or a stone, they do return it to him so that something permanent will not be in the Holy Temple, as it is said, (Ezra 4:3) It is not for you and us [to build a House to our God, but we alone will build it]. But in the case of a synagogue, they may accept it right from the start, so long as he says, "I dedicated something with the [same] intention of a Jew," and if he did not say so, it may be preserved in storage in that his intention may be for the sake of heaven. They may not accept anything [from Gentiles] for the walls of Jerusalem or for the water channel there, as it is said, (Nehemiah 2:20) But you have no share or claim or stake in Jerusalem!¹⁵¹See Babylonian Talmud Arakhin 6a.