'Once' in the Bible

Dear friends, [although I] was making every effort to write to you concerning our common salvation, I considered [it] a necessity to write to you to encourage [you] to contend for the faith delivered once and for all to the saints.

Now I want to remind you, [although] you know everything once and for all, that Jesus, having saved the people out of the land of Egypt, the second time destroyed those who did not believe.