U’v’zroa nituyah, zo haherev, With an outstretched arm – this is the sword: This is a reference to the plague of the first born. The proof text which the Haggadah brings, “His drawn sword in His hand outstretched over Jerusalem,” is a reference to a plague in the time of King David; it is also the fifth of the five plagues (as we see this from the use of the word ‘hand’ in the verse.). The word zaroah, out stretched arm, is used here instead of the word yad in order to emphasize the power of this plague, and also so that we use a different word to refer to each set of five plagues. In these two passages, then, we find a reference to all ten plagues. The recitation of the plagues is connected with these passages and not just the latter passage which begins d’var acher, “another interpretation.”