scoring and structure in the weimar version , bach scored the cantata four vocal soloists ( soprano ( s ) , alto ( a ) , tenor ( t ) and bass ) ( b ) , a four-part choir , and an orchestra of three trumpet ( tr ) , timpani ( ti ) , recorder ( fl ) or flauto traverso ( ft ) , oboe d'amore ( oa ) , two violin ( vl ) , two viola ( va ) , bassoon ( fg ) , cello ( vc ) , and basso continuo ( bc ) .