'Ink' in the Bible

You show that you are a letter from Christ, delivered by us, written not with ink but with the Spirit of the living God, not on tablets of stone but on tablets of human hearts.

I have many things to write to you, but I prefer not to do so with paper (papyrus) and black (ink); but I hope to come to you and speak with you face to face, so that your joy may be complete.

I had many things [to say when I began] to write to you, but I prefer not to put it down with pen (reed) and black (ink);