The Qur'aan established two general principles concerning the reward and punishment for deeds:

1) Each human will fundamentally only be benefited or harmed by the deeds which he or she actually did.

"...that humans will only have the result of their actions." [Soorah an-Najm (53):39]

2) No human can carry the sin of another.

"...that no one bearing sins can carry the sins of others." [Soorah an-Najm (53):38]

Consequently, when a person dies, the opportunity for that person to do good ends with the person's death. However, the chance to harvest good from deeds which were done prior to death remains.

Du'aa

The prayers of other Muslims on behalf of the dead will benefit the dead, by the permission of God. Had they done no good, no one would consider praying for them. If they were evil, the prayers of others will not benefit them. In Chapter al-Hashr (59):10, Allaah praises the believers who pray for those who have passed away before their time.

"And those who came after them say: Our Lord, forgive us and our brothers who preceded us in faith, and do not put in our hearts any hatred against the believers. Our Lord, You are indeed full of kindness, Most Merciful."

Furthermore, the funeral prayer itself consists mostly of prayers for the dead.

Safwaan [the narrator mentioned that Safwaan ibn `Abdillaah ibn Safwaan was married to ad-Dardaa] said, "I visited Abud-Dardaa's home in Syria, but did not find him there. Ummud-Dardaa asked [me], 'Are you going to make Hajj this year?'  I said:  'Yes.'  She said, 'Pray to Allaah for good for us, for the Prophet (pbuh) said, "The prayer of Muslim for his Muslim brother in his absence will be answered. As long as he prays for the good of his brother, there is an angel assigned near his head who says: Amen, and may the same be for you."’ I left and went to the marketplace where I met Abud-Dardaa and he related from the Prophet (pbuh) the same as that." [Sahih Muslim, vol.4, p.1429, no.6590.]

Fasting

Fasts missed by dead persons may be done on their behalf by their close relatives. The fasts may be from Ramalaan or from oaths (nathar).

`Aa'ishah quoted Allaah's Messenger (pbuh) as saying, "Whoever died owing fasts, his guardian should fast on his behalf" [Sahih Al-Bukhari, vol. 3, p.99, no.173, and Sahih Muslim, vol. 2, p.556, no. 2553.]

Ibn 'Abbaas said:  A man came to the Prophet (pbuh) and asked:  O Messenger of Allaah, my mother died owing one month of fasting. Should I do it for her? He replied, "Yes, debts to Allaah, have more right to be paid." [Sahih Al-Bukhari, vol. 3, p. 99, no. 174, and Sahih Muslim, vol. 2, p. 556, no. 2554.]  In another narration a woman asked about her mother’s debt of fasting and got the same reply. [Sahih Muslim, vol. 2, pp. 556-7, nos. 2554, 2557-61.]

Paying Financial Debts

Anyone may cover the debts of a dead person, whether they are relatives or not. Furthermore, the payment of outstanding debts can benefit the dead by relieving them from some of the punishment due to them for their negligence in repaying them.

Jaabir said:  A man died and we washed him, perfumed him and shrouded him.  Then we brought him to Allaah's Messenger (pbuh) to lead the funeral prayer for him.  We asked, "Could you pray for him?"   He took a step forward then asked, "Does he have any outstanding debts?" We answered:  "Two deenaars." [He said, "Make the funeral prayer for your companion," and] [This addition can be found in another narration of the hadeeth] began to leave. Aboo Qataadah took responsibility for [paying] them, saying, "The two deenaars are my responsibility."   Allaah's Messenger (pbuh) asked, "Will the creditor be taken care of and will the dead person be absolved from them?" He replied, "Yes," so the Prophet (pbuh) led the funeral prayer for him. One day later he asked [Aboo Qataadah], "What was done about the two deenaars?" He replied, "He only died yesterday!" The following day he returned to the Prophet (pbuh) and said, "I have paid them off."  The Messenger of Allaah (pbuh) said, "Now his skin has become cool." [Musnad Ahmad, vol.3, p.330; authenticated in Ahkaamul-Janaa’iz, p. 16]

The Charity of Children

Parents will benefit from whatever righteous deeds their children do, without decreasing the reward of their children's good deeds. A righteous child is considered to be part of the parent's earnings.

`Umaarah ibn `Umayr’s aunt asked `Aa’ishah, "I have an orphan under my guardianship. May I consume some of his wealth?" She replied that she had heard Allaah’s Messenger (pbuh) say, "Among the most pleasant things a man consumes is what comes from his own earnings, and his child is from his earnings." [Sunan Abu Dawud, vol. 2, p. 1002, no.3521; authenticated in Saheeh Sunan Abee Daawood, vol. 2, p. 674, no. 3013]

`Aa’ishah related that a man asked the Prophet (pbuh): My mother died suddenly, and I think that if she had spoken [before dying], she would have given something in charity. If I give charity on her behalf, will she get the reward?  He replied, "Yes." [Sahih Al-Bukhari, vol. 2, p.266, no.470, Sahih Muslim, vol. 3, p.866, no.4002, and Sunan Abu Dawud, vol. 2., p.812, no.2875]

Aboo Hurayrah quoted the Messenger of Allaah (pbuh) as saying, "When a man dies, his acts come to an end, except in three cases: an ongoing charity, knowledge from which people continue to benefit, and a righteous child who prays for him." [Sahih Muslim, vol. 3, p.867, no. 4005, and Sunan Abu Dawud, vol. 2, p.812, no.2874]