PRAYERS FOR THE DEAD.
According to the teaching of Muhammad, it is the duty of all true Muslims to pray for, the dead (Durru ‘l-Mukhtar, p 185) See also Mishkat book v chap iii.
“God most certainly exalts the degree of a virtuous servant in Paradise, and the virtuous servant says, ‘O my Lord, from whence is this exalted degree for me?’ and God says ‘It is on account of your children asking pardon for you.'”
“The Prophet passed by graves in al-Madinah and turned his face towards them, and said, ‘Peace be to you, O inhabitants of the graves! May God forgive us and you. Ye have passed on before us, and we are following you.”
“A dead person in the grave is like one over his head in water, who calls to somebody to take him by the hand. For he has hope that his father or mother, or his brother, or his friend will pray for him. For when the prayer reaches the dead person it is more esteemed by him than the whole world, and all that is in it; and verily God most certainly gives to the dead, on account of the prayers of the people of the earth rewards like mountains, for verily the offerings of the living for the dead are asking forgiveness for them.”
Surah lxxi. 29: “And Noah said, O my God, forgive me and my parents”
Surah ix 114, 115 “It is not for the Prophet to pray for the forgiveness of those, who, even though they be near of kin, associate other gods with God after it hath been made clear to them that they are to be the inmates of hell. For neither did Abraham ask forgiveness for his father, but in pursuance of a promise which he had promised him, and when it was shown him that he was an enemy of God, he declared himself clear of him vet Abraham was pitiful and kind.”
It is related in the Traditions that the Prophet visited his mother’s grave, and wept in such a way as to cause those who were standing around him to weep also. And the Prophet said, “I have asked my benefactor permission to ask pardon for my mother, which was not granted then. I asked my Lord’s permission to visit her grave and it was granted, therefore do ye visit graves, because they remind you of death.”
Based on Hughes, Dictionary of Islam