Riyad as-Salihin

Zaid bin Khalid (May Allah be pleased with him) reported: The Messenger of Allah (ﷺ) said, "He who equips a Ghazi (fighter) in the way of Allah is as if he has taken part in the fighting himself; and he who looks after the dependants of a Ghazi in his absence, is as if he has taken part in the fighting himself."

[Al-Bukhari and Muslim].