[14].Surah Ibrahim {A.S} [Abraham (PBUH)]: Ayat 16-17

Ayat 16. In front of him (every obstinate, arrogant dictator) is Hell, and he will be made to drink boiling, festering water.

Ayat 17. He will sip it unwillingly, and he will find a great difficulty to swallow it down his throat , and death will come to him from every side, yet he will not die and in front of him, will be a great torment. 

Hazrat Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah  [SAWW](PBUH) said, "Whenever someone greets me, Allah returns the soul to my body (in the grave) and I return his greeting.''

[Abu Dawud Hadith # 2041]. 

Lesson : We learn from this Hadith that the Prophet  [SAWW](PBUH) is alive in his grave and he answers the salutation offered by a Muslim. But this life of his is the life of Barzakh (an intervening state between death and the Day of Resurrection, and whoever dies, enters it) the reality of which is not known to us. Thus, it is wrong to say that the life of the Prophet  [SAWW](PBUH) is like worldly life or more vigorous than it. Such a claim is baseless because it is not confirmed by the Qur'an and Hadith. Were he to be alive the way he was in his lifetime, there would have been no need for "the returning of the soul to his body'' and he would be able to answer the salutations without it. As far this ambiguity is concerned, when countless Muslims are always offering salutations to the Prophet  [SAWW](PBUH) how does the return of the soul takes place after such short intervals? Such questions arise due to the lack of certitude in the Omnipotence of Allah. When the Prophet  [SAWW](PBUH) stated that his soul is returned to him then we should have absolute faith in his statement because Allah is Capable of doing every thing. What is its nature and form, it is not known to us, nor can we know it. Thus, the question of the return of soul in the grave should be considered similar to the ambiguous Ayat of the Qur'an in which every Muslim is required to have blind faith but their secret is known to Allah Alone. This Hadith has an inducement for offering more and more supplications for the Prophet  [SAWW](PBUH) so that the devotee is blessed with the maximum reward in the form of the Prophet's response to his salutations. It is certainly a great blessing which a Muslim should try every nerve to achieve.