It is narrated from Sayyiduna Zayd bin Khalid al-Juhani (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Whoever equips a fighter in the path of Allah has, as it were, fought himself; and whoever looks after the family of a fighter in his absence has also, as it were, fought himself."
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 5208