Whoever spends something in the cause of Allah, it will be recorded for him as much as seven hundred times
Authentic hadithعن أبي يحيى خُرَيْم بن فَاتِك رضي الله عنه مرفوعاً: «مَنْ أَنْفَقَ نَفَقَةً في سَبِيل الله كُتب له سَبْعُمِائَةِ ضِعْفٍ».
Abu Yahya Khuraym ibn Fātik (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: “Whoever spends something in the cause of Allah, it will be recorded for him as much as seven hundred times.”
Explanation
Spending anything small or little in the cause of Allah, be that in jihad or in anything that is good or helps obey Allah, yields multiplied reward up to seven hundred times on the Day of Judgment.
Source · Narrated by At-Termedhy - An-Nasaa’i - Narrated by Ahmad
From the Hadith Encyclopedia (hadeethenc.com).