The Valley of Jehoshaphat is mentioned at Joel 3:2… and translates to “valley where Yahweh judged”. It is the place where the Lord summons the nation’s for judgment.
The Kidron Valley has been associated with the Valley of Jehoshaphat since the fourth century A.D. though there is no proof Joel was referring to any particular valley. Some scholars believe the place reference is merely symbolic.
The Book of Joel advises God promised all nations they would ultimately be called to God’s place of judgement.