Abu Yahya Khuraim bin Fatik (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) said, "He who makes a contribution in Allah's way, will have his reward seven hundred times recorded to his credit."[At-Tirmidhi].
App reference: Book 12, Hadith 54
Arabic/English book reference: Book 12, Hadith 1338