Ben-David, a naturalized Israeli citizen who was born Hussam Sawafta in the West Bank town of Tubas, was found guilty earlier this month of assisting an enemy during wartime and of contact with a foreign agent. In their sentencing decision, three judges of the Haifa district court noted that these are two of the most serious crimes on Israel's law books.
The enemy agent Ben-David contacted was his brother, a Palestinian operative from Islamic Jihad, an Iranian-backed group that has killed dozens of Israelis in suicide bombings. Ben-David was convicted earlier this month of helping his brother plan a bombing attack against Israelis.
Ben-David left his home in the West Bank town of Tubas in the early 1990s, working as a laborer in Israel and later converting to Judaism, living for a time as an Orthodox Jew. He married an Israeli woman with whom he had four children and became an Israeli citizen.
Ben-David re-established contact with his family in 2006, and agreed to help his brother, Salah Sawafta, obtain a large amount of nitric acid - a chemical which can be used to manufacture bombs - according to the court documents.
Ben-David had secret contacts with his brother, changing the memory card in his cellphone to avoid leaving traces of calls to him. He later went to an Islamic religious court and converted from Judaism back to Islam, the documents said.
Salah Sawafta was killed in December 2006 by Israeli troops. Ben-David was arrested weeks later.
During the trial, Ben-David insisted he had never agreed to help his brother, and had tried to convince him to cease his militant activities.
In their decision, the judges said they took into account that Ben-David never actually purchased the nitric acid, but only agreed to do so.
"The case before us is indeed exceptional because of the defendant's personal circumstances," the judges wrote in their ruling, but said Ben-David's Israeli citizenship and his "full integration over the years in Israeli society" made his crime worse.
"An Israeli citizen collaborating with terror organizations, a domestic enemy, is one of the most serious and reprehensible phenomena that exist," they wrote.