A man who was worshipping idols
Abdul Wahid b. Zaid, one of the most famous saints narrated a real-life story. He says that once they were sailing through a sea when strong winds started to blow. The wind took them to an island. When they stopped by the island to spend the night, they saw a man there. The man was worshiping an idol.
Zaid and his companions went forth to guide the man. They asked him why was he worshiping an idol who has been created by him? They told him that the God they worship is the creator of all and thereby He alone shall be worshipped.
He was impressed by Islam
He was impressed by the religion and wanted to know more. He asked about Allah and His existence and more about the religion. When told about the Holy Prophet PBUH, he asked that where he PBUH is now.
They told that once the mission of Islam was completed, he PBUH died and reunited with Allah. He asked that is there something that has been left behind the Prophet PBUH.
They recited a few verses of the Quran
They told him that a complete code of life, complete book of guidance known as Quran has been given to us by Allah through Holy Prophet PBUH. Then they recited a few verses of the Holy Quran, upon which the man started to cry and said that indeed Islam is the true religion.
He embraced Islam
A few days later, the man fell on his deathbed. When Zaid and friends went to see him, he said that he satisfied that he is dying as a Muslim. He is a blessed one who has been guided before his death.
Zaid saw him in a dream
The man died shortly after and was buried. The very night Zaid saw a dream. He saw the deceased man in a lavishly green garden. The garden had a beautiful throne upon which a beautiful lady sat. The lady was so beautiful that he had never seen such a beauty elsewhere. She was reciting a few Quranic verses.
Indeed this story is a beautiful one: when Allah wants to guide someone, He does so by His mercy. Zaid and his companions never planned to visit that Island yet they were taken there so that they could guide the man to the right path.