Study Guide Beitzah 19 Today’s daf is sponsored by Joanna Rom in remembrance of her mother, Rose Rom (Sura Razel), on her thirteenth yahrzeit. “She is still with me every day, my inner teacher." There is a controversy as to whether it is forbidden to purify a vessel bein hashmashot (twilight) on Yom Tov only or is it forbidden also on a weekday during twilight?  What is the basis for the dispute? What is the meaning of the Mishna that one can purify a vessel from one use to another or one group to another? Beit Shamai and Beit Hillel disagree on what sacrifices can be brought on Yom Tov. There is a tanaitic debate about which types of sacrifices Beit Shamai and Beit Hillel agree on and on which they disagree. Does everyone agree that vow and gift offerings are not allowed to be sacrificed on Yom Tov? The Gemara proves that there is a dispute among tannaim on this and brings braitot to prove it. One of the braitot deals with the laws of the thanksgiving sacrifice - on which holidays is it possible/not possible to offer it? Why? And what is the controversy that appears there regarding the prohibition to not delay bringing one’s vow and gift offerings?