Kommentar zu Bereschit 43:3

העד העד [THE MAN] DID SOLEMNLY PROTEST UNTO US — The Hebrew is an expression signifying warning and it is derived from the root עוד to bear witness, because a warning is, as a rule, given in the presence of witnesses. Other examples are (Jeremiah 11:7) “I earnestly forewarned (העדותי) your fathers”, and (Exodus 19:21) “Go, warn (העד) the people.

ויאמר אליו יהודה לאמור, Yehudah said to him, saying, etc. The word לאמור here seems to mean that Yehudah made a variety of suggestions to Jacob all of which were in the nature of a reply to Jacob's arguments against sending Benjamin to Egypt. The most important of these was the reference to the Egyptian ruler's warning that the brothers would not be able to see him (and buy grain) unless they had their younger brother with them. The Torah implies that the brothers did not resort to another reply, namely that they would take Benjamin with them regardless of whether Jacob approved or not. The word לאמור then means they waited for Jacob's word, i.e. permission.

העד העיד, when a caution is issued to people in the presence of witnesses, the caution is not called התראה, “warning,” but עדות, “testimony.”