This excerpt is taken from the book Fazail al-Jihad by Sheikh Abi Abdul Sabur Abdul Ghafoor Damani.
عن أبي مسعود الأنصاري قال جاء رجل بناقة مخطومة فقال هذه في سبيل الله فقال رسول الله صلی اللہ علیہ وسلم لك بها يوم القيامة سبعمائة ناقة كلها مخطومة۔
"Abu Mas'ud Ansari, may Allah be pleased with him, narrated that a man brought a she-camel with a pack and said: 'This is for the cause of Allah.' The Messenger of Allah, peace and blessings be upon him, said: 'In return, you will have seven hundred she-camels on the Day of Resurrection, all with packs.'"
Reference: (Sahih Bukhari and Muslim) (Narrated by Muslim, Book of Leadership, Chapter on the Virtue of Charity in the Cause of Allah and its Multiplication, Number: 1892)
Explanation
One meaning of being given seven hundred she-camels in return is that on the Day of Resurrection, you will have the reward and recompense equivalent to seven hundred she-camels.
It is also possible that on the Day of Resurrection, the person will actually be given seven hundred she-camels in Paradise, and he will ride them one by one for enjoyment. Imam Nawawi, may Allah have mercy on him, states that the second meaning is more appropriate.
Reference: (Sharh Sahih Muslim by Nawawi)
