Charles H. Spurgeon on Psalms 78:49

By sending evil angels among them. That the devil and his angels are so very evil, that for them everlasting fire is prepared, no believer is ignorant: but that there should be sent by means of them an infliction from the Lord God upon certain whom he judgeth to be deserving of this punishment, seemeth to be a hard thing to those who are little prone to consider how the perfect justice of God doth use well even evil things. For these indeed, as far as regardeth their substance, what other person but himself hath made? But evil he hath not made them; yet he doth use them, inasmuch as he is good, conveniently and justly; just as on the other hand unrighteous men do use his good creatures in evil manner: God therefore doth use evil angels not only to punish evil men, as in the case of all those concerning whom the Psalm doth speak, as in the case of king Ahab, whom a spirit of lying by the will of God did beguile, in order that he might fall in war; but also to prove and make manifest good men, as he did in the case of Job. Augustine.