'Letters' in the Bible

For in our letters we say no other things to you, but those which you are reading, and to which you give agreement, and, it is my hope, will go on doing so to the end:

Do we begin again to commend ourselves? or need we, as some others, epistles of commendation to you, or letters of commendation from you?

Now if the ministry of death, chiseled in letters on stones, came with glory, so that the Israelites were not able to look directly at Moses’ face because of the glory from his face—a fading glory—

That I may not seem as if I would terrify you by letters.

For his letters, say they, are weighty and powerful; but his bodily presence is weak, and his speech contemptible.

Let such an one think this, that, such as we are in word by letters when we are absent, such will we be also in deed when we are present.