What is Hallel? Why do we say Hallel? When do we say Hallel?
Hallel is a group of Psalms, written by King David about 2500 years ago. The primary theme is that G-d controls the ups and downs of life. He challenges us to trust in Him even when things are hard, and then shows us that He is there by saving us. This theme is fitting to say during the holidays that celebrate our redemption from Egyptian slavery, namely Pesach, Shavuot and Sukkot. It is also said during Chanuka, and on Rosh Chodesh. Rosh Chodesh (the beginning of a new Jewish month) is the beginning of a new moon, which is symbolic of going from dark to light – from difficulties to being saved.