From an interview with Reb Shlomo translated from German

The Host: What do your songs sing about?

Shlomo Carlebach: My songs are… I mostly make… My thing is making melodies, and I take the words of the prophets, who talk about the great day, about peace, about the unity of the world. Sometimes I add my own words, and I tell stories. You know, the whole thing is, what is very strong in my heart, until now, all religions, but I can’t speak of all religions, I can only speak of mine, the religious people of the world so to speak, have only talked about God’s will. When you talk to a religious person, he’ll tell you right away, you have to do this, you must… Don’t do that, don’t do that. Someone who does that is bad. Always just God’s will. But very little has been said about the unity of God. 

I believe now is the time when… I mean, the unity with God. The unity with God, and if one understands the unity with God, then one understands the unity with people. Because if God is one, then the whole world is one. Listen, a great rabbi once said, have you ever heard that the left foot is evil on the right foot? If my right foot accidentally kicks my left foot, and not because of that I want to cut off my left foot, but if another person steps on my foot, then I want to cut off his feet. Why? Because he’s a stranger. But if I knew that the whole world is one, another person’s foot is my foot too. The world, as I understand it, the whole world is ready to learn from the unity of God if one would really learn it. And with my melodies, I want to, so to speak, make my little contribution to making the world one.