King James Version
I will therefore put you in remembrance, though ye once knew this, how that the Lord, having saved the people out of the land of Egypt, afterward destroyed them that believed not.English Standard Version
Now I want to remind you, although you once fully knew it, that Jesus, who saved a people out of the land of Egypt, afterward destroyed those who did not believe.Catholic Public Domain Version
So I want to caution you. Those who once knew everything that Jesus did, in saving the people from the land of Egypt, afterwards perished because they did not believe