R. Yossi Haglili says: It is written (Devarim 16:15) "Seven days shall you celebrate ('tachog') to the L–rd your G–d," to include the seven days of Pesach as requiring a chagigah. But perhaps it speaks only of Succoth? (This is not so, for Leviticus 23:41) "And you shall celebrate it as a festival of the L–rd" already speaks of Succoth. How, then, are we to understand "Seven days shall you celebrate"? To include the seven days of Pesach as requiring a chagigah.