One of the phrases I have frequently heard being both misused and abused is "correlation is not causation." Technically that is a true enough statement. Unfortunately, the way it is used is frequently misleading, contradictory, and hypocritical. Theists, or theists of a certain stripe, tend to wield it like a ignorant cudgel. Their intention is to change the subject at hand or end the argument outright. They do not get the subtle difference between saying it does not automatically follow that correlation indicates causation and the notion that with further investigation it may turn out that the specific correlation may actually mean causation.
Correlation of events, phenomena, etc. is more than enough reason to investigate. The correlation may indicate causation. There is no way to know whether it does until further investigations are made. Simply stating, "correlation is not causation", does not prove or disprove anything. Using that one set of words to end a discussion/debate or an inquiry of any type is an abuse of the concepts innate to the phrase. It is intended to convey the basic principle of the scientific method. Until you observe, test, review, and retest the statement is essentially hollow.
It is also contradictory since most of the theists who enjoy using the phrase to attack any science based arguments they come across will never apply it to their own beliefs. Nearly all of our understanding of the early formation of Christianity is based on correlation, at least to some degree. Many of the religious based reform movements we now associate with the early Christian church contain elements that predate the time frame that Jesus Christ presumably lived. A number of early scriptures that reference Christ can also be read symbolically. There is reason to believe that they require a physical being. Some of the specific early groups may not have actually been "Christian" when they initially formed but rather became "Christian." Correlating all these elements is widely seen as the cause both of the "Christ" figure we eventually named Jesus and the early Christian faith. This may be true or it may not be. It may be true that without correlation there never would have been a Christ figure to latch onto.
Correlation should encourage and inspire inquiry not stifle it.