"She's the most loving, caring, peace-seeking, justice-seeking human being," he told Reuters of the grandmother of six.
"She became an Arabic teacher and Hebrew teacher.
Sitting in his kitchen in north London, Noam Sagi, 53, said his one hope was that when the militants come face-to-face with those they have taken they will see them not as a Jew or an Israeli, but as humans.
I just hope that they will realise that you can't prioritise yours over anyone else," he said.
Hamas has vowed to execute a captive for each home hit without warning.
Persons:
Noam Sagi, Ada, Toby Melville, Ada Sagi, Noam, Nir Oz, Kate Holton, Howard Goller
Organizations:
Hamas, REUTERS, Reuters, Thomson
Locations:
London, Britain, Israel