We’ll let Mustafa do the talking here: 

"'Gaza is Calling' is about my first experience with heartbreak in friendship. I was 11 when I met this boy from Gaza. We were inseparable. With him I shared one of the deepest loves I’ve ever known, he grew up alongside me in a housing project in Toronto. And not even this love was a match for the violence we were up against; the one in our new home, the one that followed him from Gaza like a cold wind. In the end it was all the bloodshed between us that didn’t allow us to see each other without tears appearing, and one of the last notes he sent to me was about how we would continue on in another life. The string sample is the Arabian nostalgia that we share, the autotuned Arabic I sing is the balance we tried to reach being boys of cultural empires in a small hood, and the Oud is the instrument of our homelands, Sudan and Palestine. Donate here - https://www.pcrf.net/" 

And on his Instagram:

"Proceeds go to the children of Palestine. It haunts me that this song/film was written and recorded so long ago, it is also evidence of how this nightmare & occupation has always been, how before a lens there was still an angel accounting for the death of a child, the death of a freedom, death of an innocence. Before us and after us is a God who remembers, how honourable is the one who holds the memory of the dying? How can any of our hearts be still? We are mirrors at our best. Young Israa, thank you for your willingness, your performance here is the thread. May your suicidal ideation collapse along with this hell that keeps you from flying. To Ali, wherever you are, I love you, and I hate that we escaped wars in our homelands only to be met with a dark one in that small Toronto hood, a war we waged against each other. Gaza calls you still. Abdul, little brother, you are Gaza, you remind us. Bella, thank you for answering my call. & to everyone that touched this, it is because of you.”