'One' in the Bible

My loved ones, while my thoughts were full of a letter which I was going to send you about our common salvation, it was necessary for me to send you one requesting you with all my heart to go on fighting strongly for the faith which has been given to the saints once and for ever.

For certain people have crept in unnoticed [just as if they were sneaking in by a side door]. They are ungodly persons whose condemnation was predicted long ago, for they distort the grace of our God into decadence and immoral freedom [viewing it as an opportunity to do whatever they want], and deny and disown our only Master and Lord, Jesus Christ.

Now I want to remind you, although you are fully informed once for all, that the Lord, after saving a people out of the land of Egypt, subsequently destroyed those who did not believe [who refused to trust and obey and rely on Him].

Now when Michael, one of the chief angels, was fighting against the Evil One for the body of Moses, fearing to make use of violent words against him, he only said, May the Lord be your judge.

But as for you, beloved, remember the [prophetic] words spoken by the apostles of our Lord Jesus Christ.

Now to the one who is able to keep you from falling and to make you stand joyful and faultless in his glorious presence,

to the only God our Savior, through Jesus Christ our Lord, be glory, majesty, dominion, and power, before all time and now and forever. Amen.