The last bracha before saying the Shma says that Hashem selected the Jews with love. Hashem selected us and loved us from then until now. The first stanza after saying the Shma says that we will love Hashem with all our heart, soul, and might. We were selected by Hashem and love him from now until forever. That Hashem loves us from then until now, that we will love Hashem from now until then, and, it stands to reason that “Shma Yisroel, Hashem Elokeinu, Hashem Echad” is a declaration of our love for each other right now.