Sahih Muslim | Book 5 | Hadith Number 2239

Narrated by Abu Huraira
Abu Huraira reported Allah's Messenger (may peace be upon him) assaying: If anyone contributes a pair of anything for the sake of Allah, he would be invited to enter Paradise (with these words): O servant of Allah, it is good (for you). These who engage in prayer will he invited to enter by the gate of prayer; those who take part in Jihad will be Invited to enter by the gate of Jihad; those who give charity will be invited to enter by the gate of charity; and those who observe fast will be invited to enter by the gate Ar-Rayyan. Abu Bakr Siddiq said: Messenger of Allah, is it necessary that a person be invited through one of these gates? Will anyone he invited to enter by all those gates? The Messenger of Allah (way peace be upon him) said: Yes, and I hope you will be one of them.