What was the first battle against the Jews and its primary cause? Was the Prophet's migration (peace and blessings be upon him) by revelation, and who received him in Medina? What was the reason for the war against Banu al-Nadir?

The first battles of the Muslims with the Jews were with Banu Qaynuqa', and the reason was their breach of the covenant with the Messenger of Allah, peace and blessings be upon him. This occurred after the incident of the Arab woman in the Banu Qaynuqa' market whose private parts were exposed by the Jews, and the Muslim who defended her was killed. The Jews killed that Muslim, which led to the anger of the Muslims and their expulsion from Medina.

The Hijra (migration) of the Messenger of Allah, peace and blessings be upon him, to Medina was by divine revelation from Allah Almighty. He was welcomed by the Ansar, who had been awaiting his arrival, and they recognized him when Abu Bakr shaded him with his cloak.

As for the reason for the expulsion of Banu al-Nadir, it was their breach of the covenant and their attempt to assassinate the Messenger of Allah, peace and blessings be upon him, when they tried to drop a rock on him while he was seeking blood money. The Messenger of Allah, peace and blessings be upon him, besieged them until they requested expulsion in exchange for carrying their wealth on camels, excluding weapons.