Portrait of Noah's Ark by George F. Cram, published June 1882 by A. Mueller & Company, NYC.
The Wheaton professor is right: Muslims and Christians do worship the same god, even if Christians believe in the Trinity, and Muslims believe that same Trinity means Christians are not true monotheists. And when I was living in Turkey, I was surprised the degree to which this was true, in spite of the sometimes haunting sound of the call to prayer that I could hear from our apartment in Ankara five times a day that made me feel I was very far from home.
It goes almost without saying that Christianity grew out of Judaism, and that Islam was a reaction, in part, to Christianity (and that same polytheistic Trinity). In fact, of the Five Pillars of Islam, the first is that "there is no God but God" (in other words, there is only one God, and certainly no son of God or Holy Spirit), and that Muhammad is his Messenger. (Muhammad claimed no divinity for or in himself. He also respected the teachings of Jesus, who alongside, Noah, is considered a prophet in Islam.)
Once, when I took my children to the Ankara Zoo with my friend, Heleen, and her family, her husband, Willem, said:
“When I was here in December, I saw a slaughtered sheep hanging from that tree for Kurban Bayram.” He pointed. Kurban Bayram (the Feast of Sacrifice in English, or Eid-ul-Adhain in Arabic) is a four-day festival when sheep are slaughtered and their meat distributed to the poor. It is an important Muslim event that celebrates the bounty of God, and commemorates the ram Abraham sacrificed in place of his son, an essential text in Islam, Judaism, and Christianity alike.
“And Abraham lifted up his eyes, and looked, and behold behind him a ram caught in a thicket by his horns: and Abraham went and took the ram, and offered him up for a burnt offering in the stead of his son.” Genesis 22:13
“Someone sacrificed a sheep in the zoo?” I had asked.
Willem shrugged his shoulders. “Yeah,” he assured me. “It was there.”
Another time, Şükran arrived at my apartment with a celebratory dish she had made called Aşure. Aşure, or Ashura in Arabic, means ten, and Şükran told me that the tenth day of Muharram (the first month of the Islamic calendar) is considered to be the day Noah’s ark rested on dry land on Mount Ararat, and the people made a dish with whatever remained in the boat’s galley. This is why Aşure is called Noah’s Pudding in English. The pudding is made of wheat but has the consistency of tapioca and has pomegranate seeds and other good things in it. Şükran kept saying it was in celebration of “notre prophet” (our prophet), by whom she meant Noah, and explained as we ate and drank a coffee that on Aşure, people give the pudding to friends and neighbors in a gesture of charity and goodwill. (Ashura was originally an annual day of fasting that was to take place on the same day as Yom Kippur, because the Prophet Muhammad connected his new community to Jewish tradition to a great extent. He also made Friday the day of communal prayer to coincide with the Jewish Sabbath, but at noon so as not to interrupt Jewish rituals.)
I could go on, but I think it's clear that some of the rituals, the people, and the values of these religions are the same.