Then the LORD will be known to Egypt, and the Egyptians will know the LORD in that day, and will make sacrifice and offering; yes, they will make a vow to the LORD and perform it.
Isaiah 19:21
Surrounding context
19:20 And it will be for a sign and for a witness to the LORD of hosts in the land of Egypt; for they will cry to the LORD because of the oppressors, and He will send them a Savior and a Mighty One, and He will deliver them.
19:21 Then the LORD will be known to Egypt, and the Egyptians will know the LORD in that day, and will make sacrifice and offering; yes, they will make a vow to the LORD and perform it.
19:22 And the LORD will strike Egypt, He will strike and heal it; they will return to the LORD, and He will be entreated by them and heal them.