Is it true that the first to believe in the Prophet, may God bless him and grant him peace, were the four hundred rabbis, along with (As'ad Abu Karib) and Waraqah ibn Nawfal, citing what Ibn Hajar and Ibn Kathir mentioned regarding the story of Tubba' and the rabbis?

The story that Tubba' was the first to embrace Islam is not established, and there is no evidence that he, or the rabbis with him, were the first to believe in the Prophet, peace and blessings be upon him.

As for Waraqah ibn Nawfal, many scholars have paused regarding his companionship, and most of them hold that he was not the first to embrace Islam. Some have even denied his Islam altogether, though a minority of scholars—like Al-Iraqi—believe he was the first to believe, based on the hadith about the beginning of revelation.

As for the investigation into who was the first to embrace Islam, the details are as follows: - The first among free men to believe: Abu Bakr Al-Siddiq, may Allah be pleased with him. - The first among women to believe: Khadijah, may Allah be pleased with her. - The first among children to believe: Ali ibn Abi Talib, may Allah be pleased with him. - The first among freed slaves (Mawali) to believe: Zayd ibn Harithah, may Allah be pleased with him. - The first among slaves to believe: Bilal, may Allah be pleased with him.

Ibn Taymiyyah narrated a consensus on these details. There are other narrations that mention Ali, Zayd, or Khadijah as the first Muslims, but the details mentioned are the most sound and well-known.