.::One-Ummah::.

89] And We have certainly diversified for the people in this Qur’an from every (kind) of example, but most of the people refused (anything) except disbelief.
90] And they say, “We will not believe you until you break open for us from the ground a spring.
91] Or (until) you have a garden of palm tress and grapes and make rivers gush forth within them in force (and abundance).
92] Or you make the heaven fall upon us in fragments as you have claimed or you bring Allah and the angels before (us).
93] Or you have a house of gold or you ascend into the sky. And (even then), we will not believe in your ascension until you bring down to us a book we may read.” Say, “Exalted is my Lord! Was I ever but a human messenger?”
94] And what prevented the people from believing when guidance came to them except that they said, “Has Allah sent a human messenger?”
95] Say, “If there were upon the earth angels walking securely, We would have sent down to them from the heaven an angel (as a) messenger.”

[al-‘Isra’ 17:89-95]
http://quran.com/17/89-95