Riyad as-Salihin

Abu Hurairah (May Allah be pleased with him) reported: The Prophet (ﷺ) said, "One who strives to help the widows and the poor is like the one who fights in the way of Allah." The narrator said: I think that he (ﷺ) added also: "I shall regard him as the one who stands up (for prayer) without rest and as the one who observes fasts continuously".

[Al-Bukhari and Muslim].