Allah SWT says: لَا يَسْتَئْذِنُكَ الَّذِينَ يُؤْمِنُونَ بِاللَّهِ وَالْيَوْمِ الْءَاخِرِ أَنْ يُجٰهِدُوا بِأَمْوٰلِهِمْ وَأَنْفُسِهِمْ ۗ وَاللَّهُ عَلِيمٌۢ بِالْمُتَّقِينَ "Those who believe in Allah and the Last Day would not ask permission of you to be excused from striving with their wealth and their lives. And Allah is Knowing of those who fear Him." (QS. At-Tawba 9: Verse 44) * Via the Beautiful Qur'an http://quran-en.com