William Burkitt on Jude 1:5

In this, and the following verses, our apostle, to deter them from following the pernicious ways of these seducers, sets before them the several examples of God's judgments inflicted in former times upon persons guilty of such crimes as these seducers were stigmatized for, and guilty of; he begins with the Israelites in the wilderness; as they perished through unbelief, after they were brought out of Egypt, so shall revolters perish, notwithstanding their baptism, and fair beginnings.

Learn hence, 1. That God's judgments inflicted on some, are, and ought to be, warnings unto all.

2. That God's ancient judgments were ordained to be our warnings and examples; his holiness is the same as ever, his justice the same, his hatred of sin the same, and his power to revenge it the same as ever; his judgments now may be more spiritual, but they are not less terrible.

Learn, 3. That unbelief will as certainly bring destruction upon Christians now, as it did upon the Israelites of old. Did God destroy them that believed not his power then? no less will he destroy them that believe not his power now.