Sirach 16:15

15 The Lord hardened Pharaoh, that he should not know him, that his powerful works might be known to the world.

Sirach 16:15 In-Context

13 The sinner shall not escape with his spoils: and the patience of the godly shall not be frustrate.
14 Make way for every work of mercy: for every man shall find according to his works.
15 The Lord hardened Pharaoh, that he should not know him, that his powerful works might be known to the world.
16 His mercy is manifest to every creature; and he hath separated his light from the darkness with an adamant.
17 Say not thou, I will hide myself from the Lord: shall any remember me from above? I shall not be remembered among so many people: for what is my soul among such an infinite number of creatures?

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