If Rutherford were writing this today maybe he’d choose not to use the word “prophecy” in relation to things the reformers said, since the concept has become so abused. I remembered an old thread where this was talked about (you participated there Daniel but it was a long time ago); I thought Rev Winzer had some good points. He (and Chris made the same statement) said that the subject is ”best discussed under extraordinary providence, or perhaps, because that phrase is usually associated with miracles, it would be best to call it unusual providence.“ He also noted a quotation from Robert Blair concerning times of suffering, “which are times when the Lord will often undertake for His people in unusual ways.”
Jeri, I think those observations are useful (though I would question the claim about the immediate witness of the Spirit); do you have a link to the specific thread? In the section cited in the OP, Samuel Rutherford is very clear in distinguishing between the prophecies of the Reformers and immediately inspired prophecies. Consequently, these prophecies could not have been the product of immediate inspiration. The prophecies that Rutherford has in mind, which Perg cites in his post, seem to have been accurate predictions.
We could argue that these "prophets" were providentially guided to make accurate predictions, but were not immediately inspired to make infallible predictions. If their predictions had turned out to be mistaken, they would not have been false prophets; instead, they would simply have made predictions that turned out to be wrong.
Perhaps the best conclusion we can reach is to argue that Rutherford uses the word prophecy in an improper or looser sense than we normally employ the term in theological discourse. And let us not forget, we often use terms like "prophet" or "prophesy" rather loosely ourselves, such as someone's insight into a particular matter was "prophetic." We can recognise that they had remarkably accurate insight into future probable future events without concluding that they were immediately inspired by the Holy Spirit to produce an infallible prophecy.