This song is based off the 13 Midos Harachmim, how it has the power to bring us closer to Hashem with complete Teshuva.
It says “Hashem Hashem” two times to symbolize His compassion on us both before and after our sin.
It also tells us how Hashem remains unchanged because of our sins. He is and always will be the same Hashem both before and after we falter.
Enjoy and be inspired.