'You are Witnesses' in the Bible

Then Boaz said to the elders and all the people, “You are witnesses today that I have bought from the hand of Naomi all that belonged to Elimelech and all that belonged to Chilion and Mahlon.

Moreover, I have acquired Ruth the Moabitess, the widow of Mahlon, to be my wife in order to raise up the name of the deceased on his inheritance, so that the name of the deceased will not be cut off from his brothers or from the court of his birth place; you are witnesses today.”