To train our soul in this life so that “at the hour of death, [it will] ascend, in the utmost purity and sanctity and with absolute detachment.”

The Prophets and Messengers of God have been sent down for the sole purpose of guiding mankind to the straight Path of Truth. The purpose underlying Their revelation hath been to educate all men, that they may, at the hour of death, ascend, in the utmost purity and sanctity and with absolute detachment, to the throne of the Most High. 
(Baha'u'llah, Gleanings from the Writings of Baha'u'llah)