The Foundation Stone Haggadah: Themes of the Haggadah 10: Hallel
When we sing the first two paragraphs of Hallel, why don’t we sing the whole Hallel at once? Additionally, why don’t we make a blessing on the Hallel as we usually do? The answer is that we are not really saying Hallel, per say. Usually, Hallel is said over something that has already occurred. But we are not saying Hallel over something that happened, we are singing over something that is happening. Therefore, the mitzvah of the Seder night is singing, Shira, not Hallel. The Chatam Sofer says that now he can understand why we don’t stand during Hallel on Seder night. This is because we are not really saying Hallel, but singing.