'Letters' in the Bible

and he asked for letters [of authority] from him to the synagogues at Damascus, so that if he found any men or women there belonging to the Way [believers, followers of Jesus the Messiah], men and women alike, he could arrest them and bring them bound [with chains] to Jerusalem.

as the high priest and all the Council of the elders (Sanhedrin, Jewish High Court) can testify; because from them I received letters to the brothers, and I was on my way to Damascus in order to bring those [believers] who were there to Jerusalem in chains to be punished.

They said to him, “We have not received [any] letters about you from Judea, nor have any of the [Jewish] brothers come here and reported or said anything bad about you.