The rabbis advised the Quraish to ask Muhammad three questions. If he knew the answers to those questions, then he was truly a prophet. The first question was about some young men of long ago, who had left their people and had had a wondrous experience. The second question was about a traveler who had journeyed to the ends of the earth in the east and the west. The third question was about the Spirit, and what it was.
The Quraish hurriedly sent messengers to Muhammad to ask him the three questions. The Prophet told them to return the following day and he would have the answers for them. However, he failed to add, "insha Allah," that is, "if Allah wills." By the next day he had not received any revelation to help him answer the questions, and he had to ask the messengers to return the following day . This was repeated for fifteen days, while the people of Mecca laughed at Muhammad's inability to answer the three questions. Finally Jibril appeared to the Prophet, and told him the three answers. He also explained the reason for the delay. In Surah 18: 23-24, is the warning that one should not plan to do anything in the future, without saying, insha Allah. All that we hope to do is only accomplished by the will of Allah.
The first question was about some young men who remained steadfast in their worship of one God, while the rest of their people turned to the worship of idols. No one is sure of the number of youth involved. That knowledge is Allah's alone, although many scholars have disputed over the number. To escape persecution, the young men hid in a cave, where Allah caused them to fall asleep for about three hundred years (only Allah knows the exact length of time). They had a dog with them, and to anyone who happened to see them they would have appeared to be awake, and the person would have been filled with fear of them. When they finally awoke, it seemed to them as if only a short time had passed. It was when one of them was sent down to the town to buy food that they learned they had slept for centuries. The account of these sleepers is in the Quran, Surah 18:9-25.
The answer to the second question was about a great traveler identified as Zul-Qarnain, "the owner of two horns." He had great power and had been given the ways and means to do all things. He traveled to the setting of the sun, which set in a murky pool. Nearby there lived a people over whom Zul-Qarnain had authority to punish or reward. He chose to punish those who did wrong and then send them back to Allah to be further punished. Those who believed in Allah and were righteous, would be rewarded. Then he journeyed to the rising of the sun, where he found a people who had been provided with no protection against the sun. Those people he left completely alone.
As part of his answer to the second question, Muhammad gave information about a third journey which Zul-Qarnain made. He traveled to a place between two mountains, where the people understood scarcely anything about Allah. They asked for his help in building a barrier between them and two beings called Yajooj and Majooj. In return for his assistance they promised to pay tribute to him. However he did not desire tribute. He replied that the power which he received from Allah was better than any tribute which they could offer him. And so he helped them erect a barrier of iron and lead, which Yajooj and Majooj were powerless to climb over or dig through. But the Quran warns that on a day appointed by Allah, they would break out of their place of confinement and cause great destruction. This would be one of the signs that the Day of Judgment was near. The story of Zul-Qarnain can be found in the Quran 18:84-103.
The third question, about the Spirit, had the shortest answer. The Quran (17:85) says that the Spirit comes by command of Allah, and that mankind does not have the knowledge to fully understand it. The Jews disputed that they had been given full knowledge in the Torah, but Allah tells us that their knowledge is very small, in comparison to Allah's knowledge, which could not be recorded even if all the trees on earth were pens and all the seas were ink.
Muhammad having answered all their questions successfully, many other people were convinced and the number of believers increased. As the numbers of believers increased, the opposition felt increasingly threatened and resorted to persecution of the followers of Muhammad.
