John Calvin Commentary Numbers 16:49

"Now they that died by the plague were fourteen thousand and seven hundred, besides them that died about the matter of Korah." — Numbers 16:49 (ASV)

Now they who died in the plague. Already three hundred, or so, had been destroyed because of the conspiracy made with Korah; now a much larger number was added. And this, indeed, is what the wicked reap from their obstinacy: that God, being more and more provoked, redoubles His punishments, just as He threatens that, unless those whom He chastises repent, He will deal “seven times more” severely with them (Leviticus 26:18).

Therefore, let us learn, when we are warned by His rebukes, to humble ourselves promptly beneath His mighty hand, since nothing is worse than to kick against the pricks. And let us always bear in mind what the psalm says:

Be you not as the horse or as the mute, whose mouth must be held with bit and bridle; (because) many sorrows shall be to the wicked (Psalms 32:9–10).

They rebelliously exclaimed that the people of the Lord were slain when three hundred had perished. They now experience how much better it would have been to be silent before God and to give glory to His holy severity, than, instead of three hundred, to doom to destruction nearly fifty times as many. Let us, then, remember the admonition of Paul:

Let us beware lest we murmur, lest perchance the destroyer should destroy us,¹⁰² (1 Corinthians 10:10).

For nothing is less tolerable in us than that we should perversely presume to speak evil of God, when Scripture so often exhorts us to be silent in His presence.

¹⁰² It will be seen that he gives the substance, and not the actual words, of St. Paul’s exhortation.