Allah Almighty never disregards any good deed, be it from a believer or a disbeliever; He gives good reward for it. But the point here is, as a believer does good deeds, he does so with certain belief that he will be rewarded in the Hereafter; i.e. whatever he does, it’s for the sake of Allah, and he will get its reward in the Hereafter. However, there are people who are good and benevolent by nature, and many of them love their brothers and sisters in humanity, despite that they are not believers.
The Kuwaiti Encyclopedia of Islamic Jurisprudence makes it clear that there is surely a reward in this world for people who, despite lacking iman (belief), contribute to the progress of mankind, are good by nature, giving charity…etc. But the criterion for getting reward in the Hereafter is belief. This is based on the Hadith, in which the Prophet, peace and blessings be upon him, states: “Allah never disregards a good deed of a believer; he reward him for it in this world and in the Hereafter. As for a disbeliever, he is rewarded for the good deeds in this world so that when he is in the Afterlife, no more reward will be there for him.”.
Sheikh Hamed Al-`Ali, instructor of Islamic Heritage at the Faculty of Education, Kuwait and Imam of Dahiat As-Sabahiyya Mosque, states: “No one will enter Jannah (Paradise) except a believer. Almighty Allah says in the Qur’an“And the dwellers of the Fire cry out unto the dwellers of the Garden: Pour on us some water or some wherewith Allah hath provided you. They say: Lo! Allah hath forbidden both to disbelievers (in His guidance).” (Al-‘Araaf: 50)
Also the Prophet, peace and blessings be upon him, is reported to have said: “You will not enter Paradise until you believe.” (Agreed upon hadith). This is one of signs of Allah’s absolute justice, because when a disbeliever does something good in this world, he or she does it for the sake of a worldly gain, and it is granted to him/her. On the contrary, a believer does his or her action for the sake of seeking reward in the Hereafter, and it is on this basis he or she is granted reward according to his or her intention.
Thus, Allah gives everyone what he or she has striven for. The believer has striven and worked for the success in the Hereafter, and as such he or she is given the same recompense for his work. But as for the disbeliever, as long as his deeds do not spring from belief (part of which is believing in the Hereafter), then he or she is not admitted to Paradise. The Kafir, or disbeliever, does not seek or strive for what is in the Hereafter, rather he or she wants to attain the pleasures in this life such as seeking people’s admiration, peace of mind, etc. If the Kafir wishes and really seeks the reward in the Hereafter, he or she would right away believe in Allah, the Hereafter, and follow the messengers of Allah and never disbelieve in any of them, because disbelieving in anyone of them would be counted as disbelieving in all messengers since the message they all brought is the same and each Prophet believed in whoever came before him and gave glad tidings to the Prophet who would come after him.
In brief, Jannah is only granted for those who strive for it and there are some conditions to be met for a person to be admitted to Jannah. Whoever works in this life for the sake of the Hereafter and fulfills the conditions of Jannah, he or she will be admitted to it. Conversely, those who fail to work for Jannah or work for it but do not fulfil its conditions will never enter it. This is the absolute justice of Allah, and Allah does not do injustice to any body.”

Sheikh `Attiyah Saqr,former Head of Al-Azhar Fatwa Committee, states the following: “In terms of the reward of the Hereafter, it is totally agreed upon that a disbeliever receives no reward in the Hereafter nor does a believer who offers good deeds out of showing off. However, when talking about the reward of this world, the case is different in the sense that every one is paid for his deeds whether bad or good. Thus, a disbeliever receives reward for the good deeds he offers in this world. Almighty Allah says: “ And when Abraham prayed: My Lord! Make this a region of security and bestow upon its people fruits, such of them as believe in Allah and the Last Day, He answered: As for him who disbelieveth, I shall leave him in contentment for a while, then I shall compel him to the doom of fire a hapless journey’s end!” (Al-Baqarah: 126) Almighty Allah also says: “ Whoso desireth the life of the world and its pomp, We shall repay them their deeds herein, and therein they will not be wronged. Those are they for whom is naught in the Hereafter save the Fire. (All) that they contrive here is vain and (all) that they are wont to do is fruitless.” (Hud: 15-16)
All these Qur’anic verses make it clear that both a believer and a disbeliever get reward in this life for their good deeds. However, there is another reward for a believer in the Hereafter while a disbeliever is denied such a reward, due to his disbelief. Muslim reported that `Aisha, may Allah be pleased, asked the Prophet, peace and blessings be upon him: “O Messenger of Allah! It was the trait of Ibn Jud`aan in pre-Islamic period to feed the needy and keep ties of kinship, will he benefit from these good deeds?(in the Hereafter)” The Prophet, peace and blessings be upon him, said: “No, for he never said: ‘My Lord! Forgive my sin on the Day of Judgment’” i.e. he was doing all that while insisting on disbelief.”