Allaah has created man to worship Him. Allaah says (interpretation of the meaning): 

“And I (Allaah) created not the jinn and mankind except that they should worship Me (Alone)”

[al-Dhaariyaat 51:56]

Allaah has prescribed for him acts of worship by means of which he may attain great reward in this world and in the Hereafter. 

These deeds and acts of worship are not limited to this world only, rather Allaah has prescribed means of increasing one’s good deeds after one's death, namely ongoing charity (sadaqah jaariyah), as the Messenger (peace and blessings of Allaah be upon him) said: “When a man dies, his good deeds come to an end except three: ongoing charity, beneficial knowledge and a righteous son who will pray for him.” Narrated by Muslim, 3084. 

Al-Nawawi (may Allaah have mercy on him) said in Sharh Muslim: 

The scholars said: the meaning of this hadeeth is that the deeds of the deceased come to an end when he dies, and the renewal of reward ceases for him, except in these three cases, because he is the cause of them: his son is counted among his earnings, as is the knowledge that he leaves behind through teaching or writing, and ongoing charity, i.e., a waqf (Islamic endowment). End quote. 

Ibn Maajah (224) narrated that Abu Hurayrah (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “The good deeds that will reach a believer after his death are: knowledge which he learned and then spread; a righteous son whom he leaves behind; a copy of the Qur’aan that he leaves as a legacy; a mosque that he built; a house that he built for wayfarers; a canal that he dug; or charity that he gave during his lifetime when he was in good health. These deeds will reach him after his death.” Classed as hasan by al-Albaani in Saheeh Ibn Maajah. 

Ongoing charity is that which continues to earn reward after a person has died, hence many of the scholars defined it as the waqf, such as building a mosque, because the reward will continue to be earned so long as the waqf remains.  

As for that which does not bring a continual reward – such as feeding the poor and needy – it is not correct to call it ongoing charity, although it brings a great reward. 

Ibn Hazm said in al-Muhalla (8/151): Ongoing charity is that which continues to bring reward even after death. End quote. 

Shaykh Ibn ‘Uthaymeen said in Sharh Riyaadh al-Saaliheen (4/13): Ongoing charity refers to any righteous deed of a man that continues after his death. 

Whatever a person gives in charity of his wealth is his true wealth that will abide for him and benefit him. 

Al-Tirmidhi (2470) narrated that they slaughtered a sheep at the time of the Prophet (peace and blessings of Allaah be upon him) and gave it in charity except for its shoulder. The Prophet (peace and blessings of Allaah be upon him) asked ‘As’ishah, “What is left of it?” She said: “Nothing is left except the shoulder.” He said: “All of it will remain except its shoulder.” Classed as saheeh by al-Albaani in Saheeh al-Tirmidhi. 

What this means is that whatever a person eats is that which is gone and no longer remains, but that which he gives in charity is what will remain for him with Allaah and he will benefit from it on the Day of Resurrection. This hadeeth is a reference to the verse in which Allaah says (interpretation of the meaning): 

“Whatever is with you, will be exhausted, and whatever is with Allaah (of good deeds) will remain”

[al-Nahl 16:96]

The Prophet (peace and blessings of Allaah be upon him) told us that every man will be shaded by his charity on the Day of Resurrection, the day on which the sun will be brought close to people’s heads until Allaah passes judgement between them. Narrated by Ahmad, 16882; classed as saheeh by al-Albaani in Saheeh al-Jaami’, 4510. 

So hasten to give charity and strive to make your charity ongoing, so that you may benefit from it after death. We ask Allaah to help us to do that which He loves and which pleases Him.