that he heard the Messenger of Allah (ﷺ) saying: "Whoever is killed over his wealth then he is a martyr, and whoever is killed over his religion, then he is a martyr, and whoever is killed over his blood, then he is martyr, and whoever is killed over his family, then he is martyr."
Jami` at-Tirmidhi Book 16, Hadith 38
← Previous Hadith (Another chain of narration) from 'Abdullah bin 'Amr, from the Prophet (ﷺ) with similar meaning.

Jami` at-Tirmidhi Book 16, Hadith 37 Next Hadith → Yahya (one of the narrators) said: And I think it was from Rafi' bin Khadij - that 'Abdullah bin Sahl bin Zaid and Muhaiysah bin Mas'ud bin Zaid went out and when they reached Khaibar they separated while there. Then Muhayyisah found 'Abdullah bin Sahl murdered . Then he went to the Messenger of Allah (ﷺ) along with Huwayyisah bin Mas'ud and Abdur-Rahman bin Sahl. The youngest of the people, Abdur-Rahman, went to speak ahead of his companions. The Messenger of Allah (ﷺ) said to him: "Let the eldest of you speak." So he was silent and two companions spoke. So he conversed with them and they mentioned to the Messenger of Allah (ﷺ) about the murder of 'Abdullah bin Sahl. He said to them: "If fifty of you can swear an oath then you will have the right against the murderer." They said: "How can we take an oath when we did not witness it?" He said: "Then fifty of Jews can swear to clear the charge with you?" They said: "How could we accept the oaths of a disbelieving people?" So when he saw that, the Messenger of Allah (ﷺ) paid the blood-money." (Another Chain) from Sahl bin Abi Hathman and Rafi' bin Khadij, and the meaning is similar to this Hadith.

Jami` at-Tirmidhi Book 16, Hadith 39