The act of combining prayers, or what is known as jama', is normally done when one is a traveller (a musafir). However, according to some 'ulama, may Allah be well-pleased with them, even in darurah (emergency), one can combine prayers, even if one is not travelling. Dzuhur can be combined with asar, while maghrib can be combined with isha'. If one prays dzuhur and asar together during the time of dzuhur, this act of combination is called jama' taqdim. If, however, the 2 prayers are done during asar, it is called jama' ta'khir. The same terms apply when one combines maghrib and isha' together whether this is done earlier during maghrib (jama' taqdim) or later during isha' (jama' ta'khir). This is what can be called a rukhshah (flexibility) in Islam. For Allah (High and Exalted is He) Himself declares in al-Qur'an, "Allah (High and Exalted is He) wants easiness for you, and does not want hardship for you." Insha-Allah, more of this concept of jama' will be covered in upcoming posts. Insha-Allah.