According to this, the statement "You have chosen us from among all the nations, You have loved us" refers to the holiday of Pesach. In its simplest sense, it means one thing: You chose us because You loved us, and one is dependent on the other. However, according to our explanation, there are two parts to the holiday of Pesach:

1. The initial days, during which the Israelites left Egypt, and then "You have chosen us from among all the nations" was fulfilled.

2. The latter days, the days of the splitting of the Red Sea, when the great love between Israel and the Holy One, Blessed be He, was expressed, as it is said "for this the beloved praised" as we say in the liturgy (Geulah for Brit Milah): "Friends elevated You with song, they greeted You," and then "You have loved us" was fulfilled.

Therefore, we read the Scroll of Shir HaShirim on Shabbos Chol Hamoed as a prelude to the latter days of Pesach, the days of the splitting of the Red Sea, days in which love was revealed in its highest degree.