Question

Hello and blessings,
What definition can be given to the concept of testimony, in its various contexts in the Torah (the Tabernacle of Testimony, “I call heaven and earth to witness against you this day,” and the like) and in Jewish law? I seem to remember that I heard in one of your lectures a categorical distinction between legal testimony and the testimony under the wedding canopy (the latter being part of the act itself). Could you direct me to a column (or a lecture) on the matter?