'You are Witnesses' in the Bible

Then Boaz said to the leaders and all the people, "You are witnesses today that I have acquired from Naomi all that belonged to Elimelech, Kilion, and Mahlon.

I have also acquired Ruth the Moabite, the wife of Mahlon, as my wife to raise up a descendant who will inherit his property so the name of the deceased might not disappear from among his relatives and from his village. You are witnesses today."