Tosefta do Psalmów 114:8

Rabbi Eliezer says, "We snatch the matzot for the small children so that they don't fall asleep." Rabbi Yehuda said in his name, "Even if he only ate one entree, even if he only dipped one [piece of] lettuce, we snatch the matzot for the small children so that they don't fall asleep." Up until [which point in Hallel - Psalms of thanksgiving recited joyously and communally on many festivals] should one recite [before the meal]? Beit Shammai says, "Up to [the verse that ends with the phrase] 'A happy mother of children'" (Psalms 113:9). Beit Hillel says, "Up to [the verse that ends with the phrase] 'flint stone into a water-spring'" (Psalms 114:8). And one should conclude [this section of Hallel with [the blessing of] redemption. Beit Shammai, said to Beit Hillel, "And did they already go out [of Egypt at this time] that we [already] mention the going out of Egypt?" Beit Hillel said [back] to them, "Even if he waits for the call of the rooster, behold, they didn't go out until six hours into the day; how is it that he says 'the redemption' [when] they have not yet been redeemed?"