Sunan At-Tirmidhi

Narrated Zaid bin Khalid Al-Juhani: That the Messenger of Allah (ﷺ) said, ""Whoever prepares a fighter in Allah's cause, he has participated in a military expedition, and whoever watches after the family of a fighter, he has participated in a military expedition."" [Abu 'Eisa said:] This Hadith is Hasan Sahih