Al-Baqarah 2:143 وكذالك جعلناكم امة وسطا لتكونوا شهداء على الناس ويكون الرسول عليكم شهيدا وما جعلنا القبلة التي كنت عليها الا لنعلم من يتبع الرسول ممن ينقلب على عقبيه وان كانت لكبيرة الا على الذين هدى الله وما كان الله ليضيع ايمانكم ان الله بالناس لرءوف رحيم ١٤٣

Thus We have appointed you a middle nation, that ye may be witnesses against mankind, and that the messenger may be a witness against you. And We appointed the qiblah which ye formerly observed only that We might know him who followeth the messenger, from him who turneth on his heels. In truth it was a hard (test) save for those whom Allah guided. But it was not Allah's purpose that your faith should be in vain, for Allah is Full of Pity, Merciful toward mankind.