from his father, from his grandfather that the Messenger of Allah (ﷺ) said: "The Muslim is not killed for disbeliever."

And with this chain, it has been narrated that the Prophet (ﷺ) said: "The blood-money paid for disbeliever is half of the blood-money paid for a believer."
Jami` at-Tirmidhi Book 16, Hadith 29
← Previous Hadith "I said to 'Ali: O Commander of the Believers! Do you have anything written that is not in Allah's Book?' He said: 'By the One Who splits the seed and creates the soul, I have not learned from it except what understanding of the Qur'an Allah gives to a man, and what is in this sheet of paper.' I said: 'What is in the paper?' He said: 'It is the 'Aql, the (ransom for) release of captives, and the judgement that no believer is killed for a disbeliever.'"

Jami` at-Tirmidhi Book 16, Hadith 28 Next Hadith → that the Messenger of Allah (ﷺ) said: "Whoever kills his slave, then we will kill him, and whoever maims his slave, then we will maim him."

Jami` at-Tirmidhi Book 16, Hadith 30