John Calvin Reformed @genevareformer

17. But, beloved. To a most ancient prophecy he now adds the admonitions of the apostles, the memory of whom was recent. As to the verb μνήσθητε, it makes no great difference, whether you read it as declarative or as an exhortation; for the meaning remains the same, that being fortified by the prediction he quotes, they ought to be terrified.

Matthew Henry Presbyterian @wholebiblehenry

Here, I. The apostle enlarges further on the character of these evil men and seducers: they are murmurers, complainers, etc., Jde 1:16. Observe, A murmuring complaining temper, indulged and expressed, lays men under a very bad character; such are very weak at least, and for the most part very wicked.

Commenting on Jude 1:16-25

John Gill Reformed Baptist @doctorgill

But, beloved,.... Or "my beloved", as the Syriac and Arabic versions read; or "our brethren", as the Ethiopic version; the apostle addresses the saints in this manner, to distinguish them from the false teachers, and to show that he had a different opinion of them from them; and that be would have them beware of them, and not be surprised at them, since it was...