CAIRO — Nearly three years ago, a leader of the Muslim Brotherhood delivered a speech urging Egyptians to “nurse our children and our grandchildren on hatred” for Jews and Zionists. In a television interview months later, the same leader described Zionists as “these bloodsuckers who attack the Palestinians, these warmongers, the descendants of apes and pigs.”

That leader, Mohamed Morsi, is now president of Egypt — and his comments may be coming back to haunt him.

Since beginning his campaign for president, Mr. Morsi has promised to uphold Egypt’s treaty with Israel and to seek peace in the region. In recent months, he has begun to forge a personal bond with President Obama around their successful efforts to broker a truce between Israel and Palestinian militants of the Gaza Strip.

But the exposure this month of his virulent comments from 2010, both documented on video, have revealed sharp anti-Semitic and anti-Western sentiments, raising questions about Mr. Morsi’s efforts to present himself as a force for moderation and stability. Instead, the disclosures have strengthened the position of those who say Israel’s Arab neighbors are unwilling to commit to peace with the Jewish state.