The correlation between Judeo-Christianity and lack of corruption is negligible. There are plenty of Christian countries with endemic corruption, and several non-Christian countries without (Japan comes to mind).
The correlation between countries which do not pay their civil servants a living/middle-class wage and corruption is a much better direction for your suppositions.
The correlation between countries which do not pay their civil servants a living/middle-class wage and corruption is a much better direction for your suppositions.