According to Tafsir ibn Kathir, a classical Tafsir (i.e. a commentary of the Quran written by Islamic scholar Ibn Kathir), the Arabic word 'Khushoo' encompasses the meanings of calmness, serenity, tranquility, dignity, and humility.", while Ibn Abbas explains 'Khashi'oon' to mean, with fear and tranquility. Al-Khushoo is a necessary component of Salaah, however can be very easily lost. In a hadith, Muhammad said ""The first thing to be lifted up (taken away) from this Ummah will be al-Khushoo; until you will see n o one who has al-Khushoo.""