Ibn Mas'ud said, "When 'Umar died nine-tenth of all knowledge vanished with him." The people were shocked and said, "How can this be when among us now are still many of the great companions?" Ibn Mas'ud replied,"I am not speaking of the knowledge of fiqh and the science of judgements, I'm speaking about the knowledge of Allah." This struggle of isolation, hunger, sleeplessness, weeping, fear and endless service to men was for this end. The journey is only for knowledge of Allah and the whole of it lies in detachment from everything that passes away. First from what is displeasing to Allah, then from one's self-illusion and desires, and then from all men and all otherness until there is only isolation and extreme nearness to Allah.
Khalid Muhammad Khalid, Men Around The Messenger: The Companions Of The Prophet
allah, inspirational, islam, sahabah, umar-ibn-al-khattab