Exegesis of the saying of Allah the Exalted: “Alif, Lam, Meem. The Romans have been defeated”

Question:
What is the exegesis of these noble verses, including the saying of Allah the Exalted: The Romans have been defeated in the nearest land, and they, after their defeat, will prevail [Surat al-Rum: 1-3]. I ask the honorable Shaykh to explain these noble verses and to identify who the Romans mentioned in them are.

Answer:
The Romans are: the well-known Christians. The wars between them and the Persians were back and forth; sometimes these would prevail over those, and sometimes those over these. Allah (Glorified and Exalted is He) informed that they were defeated; the Persians defeated them: in a few years. To Allah belongs the command, before and after. And on that day the believers will rejoice [Surat al-Rum: 3-4].
So that happened, and the Romans defeated the Persians. That was at the beginning of the Prophet’s (peace and blessings be upon him) mission, when the Messenger (peace and blessings be upon him) was in Makkah. That was among the signs and proofs of his (peace and blessings be upon him) truthfulness and that he is truly the Messenger of Allah, because the matter occurred exactly as Allah had informed in His great Book.
So Allah (Mighty and Majestic) is the Knower of the unseen, and He informs His Prophet of whatever He wills of it , just as He informed him of much of what will happen in the end times, and just as He informed him of what passed in time; of the news of ‘Ad, Thamud, the people of Noah, Pharaoh, and others. And just as He also informed him (peace and blessings be upon him) of what will happen on the Day of Resurrection, and of the state of the people of Paradise and the people of the Fire, and so on.
This is part of the unseen news that the Qur'an reported, and it came to pass exactly as reported. This was a sign of the truthfulness of the Messenger Muhammad (peace and blessings be upon him). The Muslims rejoiced over this because the Romans were closer to the Muslims than the Persians, for the Romans are People of the Book, while the Persians were worshippers of idols. For this reason, he (peace and blessings be upon him) said: : with the help of Allah the verse [al-Rum: 4-5].