Joshua 22:34

So the Reubenites and Gadites named the altar Witness, for they said, “It is a witness between us that the Lord is God.”

Note Literally named the altar, for

BSB · Berean Standard Bible
And the children of Reuben and the children of Gad called the altar Ed: for it shall be a witness between us that the Lord is God.

Note Ed: that is, A witness

KJV · King James Version
The children of Reuben and the children of Gad named the altar “A Witness Between Us that the Lord is God.”
WEB · World English Bible
And the children of Reuben and the children of Gad called the altar Ed: For, said they, it is a witness between us that Jehovah is God.
ASV · American Standard Version

Related passages

From the Treasury of Scripture Knowledge, grouped by the word they explain.

Ed
i.e, a witness. The word witness, or testimony, is not found in the common editions of the Hebrew Bible; and is supplied in Italics by our venerable translators, at least in our modern copies; for in the first edition of this translation, it stands in the text without any note of this kind; but it is found in several of Kennicott's and De Rossi's MSS., and also in the Syriac and Arabic. Several also of the early printed editions of the Hebrew Bible have the word {ed,} either in the text or in the margin; and it must be allowed to be necessary to complete the sense. It is very probable that an inscription was put on this altar, signifying the purpose for which it was erected. Thus was this affair most happily terminated.
Joshua 22:27; Joshua 24:27; 1 Kings 18:39; Isaiah 43:10; Matthew 4:10