“In addition to all your other detestable practices, you brought foreigners uncircumcised in heart and flesh into my sanctuary, desecrating my temple while you offered me food, fat and blood, and you broke my covenant. Instead of carrying out your duty in regard to my holy things, you put others in charge of my sanctuary. This is what the Sovereign LORD says: No foreigner uncircumcised in heart and flesh is to enter my sanctuary, not even the foreigners who live among the Israelites.” (Ezek. 44:7-9)
The High Priest is in charge of the Temple. Being uncircumcised in heart means that whoever the Jews will put in charge will not be a Christian. Being uncircumcised in flesh means he will not be a Jew, either. Since the Islamic Caliph will also be a Holy man, it would be proper for him to serve as the head of his religion and officiate in the Temple. We already know that the anti-Christ will set himself up in the Temple and make his claim to deity there. (2 Thes. 2:4) It’s no stretch to imagine him naming either himself or his false prophet to the office of High Priest.
Remember all the believing Jews will be warned to flee into the mountains as soon as the anti-Christ is revealed (Matt. 24:15-16) The unbelieving Jews who are left will make a “covenant with death” (Isaiah 28:15). This is when they will fulfill the Lord’s prophecy that having rejected the One who came in the Father’s name, they will accept the one who comes in his own name.