How can the Prophet exist, and yet in his time, there was one more knowledgeable than him?

The exegetes differed regarding the identity of the one who had knowledge from the Book. The majority of them held that he was Asaf ibn Barkhiya, Solomon's minister who knew God's Greatest Name (al-Ism al-A'ẓam). It was also said that he was Solomon himself, citing his saying: "This is by the grace of my Lord." And it was said that he was Gabriel, peace be upon him. There is nothing in the Quran or Sunnah that specifies his identity or the method by which he brought the throne of Bilqis. If he was a man from the Children of Israel who knew God's Greatest Name, then this was a favor bestowed upon him and a miracle for Solomon. The fact that he was more knowledgeable than Solomon in this matter does no harm, just as it happened with Moses and Al-Khidr. Sheikh al-Islam Ibn Taymiyyah considered what occurred at his hands to be among the miracles performed by non-prophets, falling under the category of unveiling (kashf) and knowledge.