Why do Jews use a shankbone at Passover when the Bible commands lamb (Ex. 12:6)? Why eat a hard-boiled egg? Should we use wine or grape juice at the seder? Is Passover the 14th or 15th of Abib (Lev. 23:5)? What is the definition of leaven? Is Pentecost Sivan 6 or Sunday? Why celebrate two days of Rosh HaShanah when the Bible only commands one? Should we blow a ram's horn (Lev. 23:24) even if we don't see the crescent? What does it mean to "afflict your soul" on Yom Kippur (Isa. 58:3)? Should we wave palm branches or build sukkahs with them (Neh. 8:15)? Why take down the sukkah on the eighth day? What does it all mean? What future events are foreshadowed by these festivals (Col. 2:17)?