"We hope and pray that he'll return to us because he belongs with us," said Shabat in a clip about the song.
"We are trying to awake something so that this doesn't sit in quiet again," added Alene in the clip.
The background of the music video shows the statement "six years in isolation," using a Hebrew word which also means quarantine.
Video of Mengistu's capture is shown in the video as the words "We're waiting for you: When will you return? Be strong. Take heart. We're with you" are said in Amharic, the language of the Ethiopian community.
The music video ends with an outline of Mengistu's face formed from the words "Avera is still alive."
"If there's something that can penetrate the indifference of people, it's music," said Eleanor Amid, from the "Friends of Avera" group. "We're a diverse group of people who understand that we need to help Avera, to hear his voice. His voice isn't heard."
"Understand the pain of the mother, understand the pain of the parents, of the siblings, of Avera," said Tanat Warkana from Friends of Avera.
Mengistu, who suffers from mental illness, has been held captive by Hamas in the Gaza Strip since he crossed into the coastal enclave in September 2014.