There are some misconceptions that get straightened out for the reader by Dr. Abuelaish's story. First, there is the misconception that Arab Palestinian Muslims and Israeli Jews cannot coexist. This is obviously not the case historically, and Abuelaish himself demonstrates that it is absolutely possible to live at peace, but it only happens by treating all humans with dignity and honor, and by choosing forgiveness instead of violence.
This is never more clear than when the families of the Israelites send their pregnant to Dr. Abuelaish to deliver their babies. Meanwhile, Abuelaish's community is literally being bombed by the Israeli Army, so it's a perfect picture of Abuelaish's commitment to treating all people with honor. He "will not hate," as the title suggests.
This commitment is brought to its ultimate conclusion when Abuelaish suffers the gruesome, traumatic, untimely deaths of his daughters. When a bomb hits their home, the girls all die suddenly, without warning, in front of Abuelaish's own eyes. Certainly now, after having lost everything valuable to him, for nothing, Abuelaish has more than enough reason to lose his cool, calm commitment to pacifism, to seek justice and revenge for himself and his daughters.
But instead, he moves to Canada and dedicates his life to finding peace. The title argument still remains, and Abuelaish has proven his commitment non-violence; He simply will not resort to hatred against another human being.