Here is Peter Kreeft, a devout follower of apostate Roman Catholicism, who is still accepted as a respected  "Christian" apologist from his travesty titled Ecumenical Jihad:

there is Christian-Muslim ecumenicism… Nothing in the Jewish Scriptures contradicts Christianity, but some things in the Qur’an do. Yet even here an "ecumenical jihad" is possible and called for, for the simple and strong reason that Muslims and Christians preach and practice the same First Commandment: islam, total surrender, submission of the human will to the divine will.

We fight side by side not only because we face a common enemy but above all because we serve and worship the same divine Commander. Many Christians, both Protestant and Catholic, do not believe what the Church says about Islam (for example, in Vatican II and in the new Catechism): that Allah is not another God, that we worship the same God… (30)

Why is Islam expanding so spectacularly? Sociologists and physchologists and historians andeconomists and demographers and politicians are quick to explain this growth with "expert" worldly wisdom from each of their specialties; but to any Christian familiar with the Bible, the answer is obvious: because God keeps His promises and blesses those who obey His laws and fear Him… (38)

THE CHURCH OF ROME AND ISLAM WORSHIP THE SAME GOD