In fifth book of the Prophet Moses, Deuteronomy, Chapter 18:18-19, God told Moses:
"I will raise up a prophet from among their brethren like you, and I will put My words in his mouth, and he shall speak to them all that I commanded him. And it will come about that whoever will not listen to My words which he shall speak in My name, I Myself will require it of him."
The question comes as to who are "their brethren?" ["a-hey-hem," in the Hebrew language of the Bible].
The prophecy was given through the prophet Moses, who was the leader of the sons of Israel during the time of the Exodus from ancient Egypt. The word "their" refers to the sons of Israel.
The word "brethren" [or "brothers" in Hebrew] is more interesting. Does it refer to sons of Israel or more distant relatives such as other sons of the Prophet Abraham, including those of the Arabs and even the Meccan tribe of the Quraysh?
The word "brother" in Hebrew, the language of the Old Testament is "ah." The same word is used in the Arabic language (sura 5:30). The "a" is long. The "h" is hard, sounding something like the sound of the "ch" in the Scottish word "loch." In "their brethren?" ["ah-ey-hem] the "ey-hem" is the ending indicating "their." Both Hebrew and Arabic as Semitic languages put various endings on words to indicate plural, possession, etc.
The same Hebrew word for "brother" is used in these ways in the books of prophecy given by Allah through Moses:
The Levites, the priestly tribe, were brethren (Deuteronomy 18:2 and 10:9)
The king of Israel is to come from the brothers (Deut 17:15)
The king of Israel is not to raise himself over his brothers (Deut 17:20)
Brother Israelites as different from aliens (Deut 1:16)
Brothers, the sons of Israel (Deut 3:18)
Brothers Israelites as distinct from foreigners (Deut 15:2-3)
Brother Israelites (Deut 15:7 & 11)
Brother Israelites at war (Deut 20:8)
Brothers among the tribes of Israel (Deut 33:9 & 16 & 24)
Brothers, Cain and Abel (Genesis 4:2-11)
Abraham, half-brother of Sarah (Gen 20:5-16)
Brothers Esau and Jacob the sons of Isaac and Rebekah (Gen 25:26)
But the two times when the distant relatives were identified as "brothers," they were spelled out and specifically identified by their name and relationship or location:
"Brothers, sons of Esau" (Deut 2:4 & 8)
"Brothers of Edom" (Numbers 20:14)
Because the law and prophecy given by Allah through the prophet Moses used the word "brother/brothers" [when only by itself] to mean only sons of Israel, the prophecy in Deut 18:18, should also be understood to refer only to a prophet who would come from the sons of Israel, not from some more distant relationship
Jesus stated that Moses wrote about Him (Luke 24:27 and John 5:46).
Luke 24:44 - And he said unto them, These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, concerning me.
John 5:46 - For had ye believed Moses, ye would have believed me; for he wrote of me.
Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken: Ought not Christ to have suffered these things, and to enter into his glory? And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself. Luke 24:25-27