Validity: The passage explicitly states that the argument applies to any infallibly foreknown act of any human being, and draws the conclusion that if a being infallibly knows everything future, no human has control over the future—the extracted argument faithfully captures this generalization step.
Confidence: The passage states the conclusion explicitly and offers the generalizability of the argument as the premise. The underlying argument structure is clear, though the referenced 'same argument' is not fully spelled out in this excerpt.