The judge, king, or high priest with official authority putting one on his solemn oath; entailing the obligation of witnessing (Leviticus 5:1). So Saul adjured the people not to eat until evening (1 Samuel 14:24-28). And Ahab adjured Micaiah to tell the truth, which elicited from him the real result of the approaching battle, after a previous ironical reply. Compare Song of Solomon 2:7 margin; Mark 5:7; Acts 19:13; 1 Thessalonians 5:27 margin.
Paul "adjuring" the Thessalonians "by the Lord that the epistle might be read to all the holy brethren." Jesus, who, as the meek "Lamb dumb before His shearers," would not reply to false charges, when "adjured (exorkizo se) by the living God," by the high priest, to tell the truth whether He be the Christ the Son of God, witnessed the truth concerning His Messiahship and His future advent in glory as the Son of man, which immediately brought on Him sentence of death. We Christians can so far join with the high priest's reply, "What further need have we of witnesses?" (Matthew 26:63-65.) Christ's own witness alone is enough to assure us of His Godhead, the truth which He sealed with His blood.