Deuteronomy 6:4

שְׁמַע יִשְׂרָאֵל ה’ אֱלֹקינוּ ה’ אֶחָד

Listen, Israel: Hashem is our G-d. Hashem is One.

Ramban starts by citing Rashi, that Hashem is currently our G-d but He is not He is not recognized as G-d by the nations of the world; in the future, He will be recognized by all and will be One. Ramban continues by pointing out that when addressing the Jews, the Torah typically refers to G-d as “Hashem your G-d.” Here, it calls Him “Hashem our G-d” as a sign of His unity.