In every place God has left Himself a witness to the truth. “Replacement Theology” (by whatever name) presumes that God has either abandoned or else fulfilled His covenant promises with Israel as a specific and particular nation, and has moved on to the Church as the replacement of Israel. Islam, of course, says that God has finished with both Israel and the Church — the one for not accepting Yeshua as the Messiah; the other for disobeying Jesus who commanded His disciples to love their enemies. Judaism replaces the commandments of God with those of men, and every one else follows suit, being that people are the same, given the circumstances, time, and the opportunity. Thank the one true God that He has other and better plans than that!
The Islamic caliphate is the Muslim religious, political, legislative, and military empire that removes boundaries of nations, using force and fear to accomplish its goal of ruling the world, with everyone submitting to their god, who is not the same God as YHVH — God the Father, the Son, and the Holy Spirit. The caliphate is ruled by the caliph (pronounce khalif in Arabic), which means ‘successor’. The main division within Islam is between the Sunnis and the Shias as to who is the proper successor, or heir, to Mohammed’s legacy and authority in the Muslim world and empire.
Of course, the true Successor and Heir of the world is the Lord Jesus Christ/Yeshua the Messiah! (Heb 1:2) The covenants of God have all been with and through Israel (Rom 9:4-5), and confirmed by God through the resurrection of Yeshua. (Rom 15:8-9) The anti-christ will also claim loyalty that only belongs to the true Messiah and Son of God, and will willfully set himself up in opposition to Jesus, and against His people, whether Jewish or Christian.
What is revealing here is that the Hebrew word used for caliphate is khalifut חליפות. This word would mean something to the effect of ‘that which has exchanged, or replaced’. In this case, the Islamic caliphate is rebelliously seeking to replace the true universal Kingdom of the true God with its own desolate counterfeit. The caliph is usurping the place of the true Successor and Heir as ‘king’ over the kingdom, by killing or subjugating Christians and Jews, and even other disagreeable Muslims, presuming to inherit the promise. (see also Mt 21:33-42; Ezek 35) We are indeed living in momentous times. Satan knows that his time is getting shorter!
YHVH God sits in the heavens, and derisively laughs to scorn those who think to replace His Son as King in Zion over Israel and the nations. Yeshua/Jesus is God of gods, Lord of lords, King of kings: every knee will bow, every tongue will confess that Yeshua the Messiah/Jesus Christ is LORD (YHVH)! Even so, come, Lord Jesus!