It is clear from the Book of Mormon usage of the verb “to witness” as it relates to baptism (see Mosiah 18:10) and the sacrament (see 3 Nephi 18:11) that it means to enter into a solemn covenant. Another way this phrase could read is “and covenant with thee.” Only when we understand that as we “witness” we are covenanting with the Father to do certain things does the ordinance of the sacrament truly become a renewal of our previous covenants taken at baptism.