Answer:
It does commit a fallacy, specifically, it does not commit a false cause fallacy.
Explanation:
The argument presented above presents a fallacy, specifically, a fallacy known as the Argumentum ad verecundiam, or appeal to authority. This kind of fallacy occurs when a relevant personality is used as a justification to support a false argument. In the case of the argument presented in the text above, the speaker uses the authority that the pastor presents in his life, to justify the argument that existentialism is bad.