يَا أَيُّهَا الَّذِينَ آمَنُواْ ادْخُلُواْ فِي السِّلْمِ كَآفَّةً وَلاَ تَتَّبِعُواْ خُطُوَاتِ الشَّيْطَانِ إِنَّهُ لَكُمْ عَدُوٌّ مُّبِينٌ

(2:208) O Believers, enter completely into Islam and do not follow in the footsteps of Satan, for he is your avowed enemy.
God demands that man should submit, without reservation, the whole of his being to His will. Man's outlook, intellectual pursuits, behaviour, interaction with other people and modes of endeavour should all be completely subordinate to Islam. God does not accept the splitting up of human life into separate compartments, some governed by the teachings of Islam and others exempt. (Tafheemul Quran)