Wisdom 18:13

13 For whereas they would not believe any thing by reason of the enchantments; upon the destruction of the firstborn, they acknowledged this people to be the sons of God.

Wisdom 18:13 In-Context

11 The master and the servant were punished after one manner; and like as the king, so suffered the common person.
12 So they all together had innumerable dead with one kind of death; neither were the living sufficient to bury them: for in one moment the noblest offspring of them was destroyed.
13 For whereas they would not believe any thing by reason of the enchantments; upon the destruction of the firstborn, they acknowledged this people to be the sons of God.
14 For while all things were in quiet silence, and that night was in the midst of her swift course,
15 Thine Almighty word leaped down from heaven out of thy royal throne, as a fierce man of war into the midst of a land of destruction,

The Brenton translation of the Septuagint is in the public domain.