Liturgy do Izajasza 47:22

The congregation did Hadassah [Esther] bring in to triple a fast on Pesach; the head of the house of evil [Haman] did you crush on a tree of fifty [amot] on Pesach; these two [plagues as per Isaiah 47:9] will you bring in an instant to the Utsi [Esav] on Pesach; embolden Your hand, raise Your right hand, as on the night You were sanctified on the festival of Pesach. "And you shall say, 'it is the Pesach sacrifice'"