Yahya bin Aadm bin Sulaiman يحيى بن آدم بن سليمان · The Book on Virtues of Jihad

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." This Hadith is Hasan Sahih.

"I heard my father saying in the presence of the enemy: 'The Messenger of Allah (ﷺ) said: "Indeed, the gates of Paradise are under the shadows of the swords.'" A man among the people with ragged appearance said: 'Have you heard what you mentioned from the Messenger of Allah (ﷺ) ?' He said: 'Yes.' So he returned to his comrades and bid them Salam (farewell), broke the sheath of his sword, and began fighting with it until he was killed."…