Alongside his pious spiritual beliefs, however, came fearful views of Jews and Israel.
Then, when Alshareef travelled to Paris to study French he was placed with a family with whom he would live and practise his language skills.
"I entered their house and saw a big Magen David and was like, ‘whaaa’,” he said.
Alshareef immediately got in touch with the organisers of his study abroad programme to request that he be moved.
“I’m not so proud of the email but I’m proud god put me through this for a reason,” he added.
The mother of his host family was “amazing,” he said, recalling his first introduction to Jewish culture and the Hebrew language.
After realising that his hosts were good people, and even taking part in Friday night dinners with them, Alshareef’s point of view was changed.
When he went home, his mother gave him two weeks to go back to his “Salafi ways,” but he found that the change in his mindset was more permanent.
Back in Saudi Arabia, the young student was inspired to create an educational project by tikkun olam – the Jewish concept that we are obliged to improve the world.
Now, Alshareef broadcasts the value of peace between Muslims and Jews to over 100,000 followers on Instagram and nearly 200,000 on Twitter.
"I care about my fellow Muslims,” he told attendees. "I want peace… the emnity between Muslims and Jews is not eternal.”
But, he added, "In these times of hardship it’s hard to convince everyone of peace.”
Israel’s war against Hamas, he argued, had made the prospect of reconciliation more remote.
"What’s happening in Gaza is terrible,” Alshareef said. “Of course no one wants to see the deaths… the war can end not this month, not this week but now if two things happen: Hamas lays down their weapons and releases the hostages.”
When confronted by other Muslims about his support for Zionism, Alshareef said, he now asks them one question: “Please define Zionism.”
The campaigner added: “Zionism can be defined in one line: the right of Jews to have self-determination in their ancestoral homeland.”
For peace to be established between Israel and Palestine, Alshareef continued, Hamas must be defeated.
"Even the Arab leaders, they always state that the only legitimate representative of the Palestinian people is the Palestinian Authority,” he said.
"Leave politics aside, everyone deep down knows that these people should not rule Gaza after the war and they do not represent the aspirations of the Palestinian people.”
"I tell my fellow Muslims who are moderate Muslims… this is not how we are destined together. We are destined to live together in the Middle East in peace.”
