Abu Bakrah Radhiyallahu Anhu narrates that someone said to the Prophet Sallallahu Alayhi Wasallam, “O Apostle of Allah! Who is better among men (i.e., what kind of a man will be successful in the Hereafter)?” The Prophet sallallahu alayhi wasallam replied, “He who lived long and did good deeds.” The same person then asked, “Who is bad to a greater degree among men (i.e., what kind of man will be a loser in the Hereafter)?” The Prophet sallallahu alayhi wasallam replied, “He who lived long and did evil deeds.” (Musnad-i-Ahmad)
The longer a person who leads a virtuous life lives, the more will he develop to a higher religious state. In a similar way, the bondsman whose deeds are such as to make him removed from Allah will go incurring His displeasure as he continues to live.
Ubayd Ibne Khalid radhiyallahu anhu narrates that once the Prophet sallallahu alayhi wasallam established “brotherly relationship” between two persons (i.e., declared them to be brothers according to the custom of the age). It so happened, soon afterwards, that one of them got killed in jehad and the other, too, died within a week of it. The Companions offered the funeral prayers at the latter’s death. The Prophet sallallahu alayhi wasallam then asked the Companions who had performed the burial service, “What did you say in the funeral salaat (i.e., what prayer did you make for the sake of your dead brother)?” The Companions replied, “We prayed that Allah may forgive his sins and have mercy on him and make him join his brother (so that they may live together in Heaven as they did in the world)”. On hearing this, the Prophet sallallahu alayhi wasallam remarked, “And where did the prayers go which he offered after the prayers of the martyred brother?” (i.e., after the chain of his prayers had been terminated due to falling a martyr in jehad). “And where did the good deeds go that he performed after the good deeds of the martyred brother?” [Or, the Prophet sallallahu alayhi wasallam said something to the effect that where did the fasts go that he kept after the fasts of his martyred brother? (The narrator is not sure whether the Prophet sallallahu alayhi wasallam mentioned, 'good deeds' after 'prayers' or 'fasts')]. The Prophet sallallahu alayhi wasallam then said, “The difference between the stations of the two is even greater than that between the heavens and the earth.”
(Abu Dawood and Nasa’i)
The Companions considered the brother who had died later to be of a lower rank than the one who had attained martyrdom in jehad, and that was why they prayed that Allah might join him with the martyred brother in Heaven. But the Prophet sallallahu alayhi wasallam told them that it was just the opposite of it and the brother who had died a natural death had gained a much more elevated position owing to the prayers he had offered, the fasts he had kept and the other good deeds he had performed after the martyrdom of his brother.
To lay down one’s life in the path of Allah is, doubtlessly, an act of a very high order, but the advance and improvement affected through Salaat, fasting and other virtuous deeds, provided that these are endured with earnestness, is also unlimited.
Besides, since the brother who died later was also a soldier of Allah, ever-willing to sacrifice his life in His path, he too had, because of the purity of his intention and eagerness for martyrdom, attained the state of martyrdom though he had died in his bed, and the acts of worship and other good deeds he had performed after the death of his martyred brother had produced such an elevation in his ranks that the sacred Prophet sallallahu alayhi wasallam described the difference between their stations in the Hereafter to be even greater than between the earth and the sky.