'Letter' in the Bible

That you may not be moved in mind or troubled by a spirit, or by a word, or by a letter as from us, with the suggestion that the day of the Lord is even now come;

So then, brothers, be strong in purpose, and keep the teaching which has been given to you by word or by letter from us.

And if any man does not give attention to what we have said in this letter, take note of that man, and keep away from him, so that he may be shamed.

These words of love to you at the end are in my writing, Paul's writing, and this is the mark of every letter from me.