One of the events that was brought up multiple times in class was the killing of the English Admiral, and the reason behind it, namely he wasn't ruthless enough. Beyond the political implications of this, and given what else we know about Voltaire, it would not be a stretch to say that this passage is also meant to make fun of religion. In the Book of Samuel, in the Old Testament, we get the story of Saul, the first Israelite king. God instructs Saul to slaughter the Amalekites, one of the neighboring tribes of the region, down to the women, children, and animals. Saul is not to take prisoners. Saul is able to crush the Amalekites, but his soldiers take women as concubines, take animals as prizes, and leave the buildings standing. This displeases God, and God takes his revenge by violently deposing Saul through David.
It should not take much of a stretch of the imagination to see the parallel between Saul's story and the story of the admiral. The admiral also had his career violently shortened by allies because he was not ruthless enough to the enemy. Voltaire could well be using this story to point out how we react poorly to the English pulling much the same stunt as God, but not many in his day would dare question the will of God, even when the actions are so equivocal.