`Umar (after he was stabbed), instructed (his would-be-successor) saying, "I urge him (i.e. the new Caliph) to take care of those non-Muslims who are under the protection of Allah and His Apostle in that he should observe the convention agreed upon with them, and fight on their behalf (to secure their safety) and he should not over-tax them beyond their capability."
Sahih al-Bukhari Book 56, Hadith 258
← Previous Hadith "An infidel spy came to the Prophet (ﷺ) while he was on a journey. The spy sat with the companions of the Prophet (ﷺ) and started talking and then went away. The Prophet (ﷺ) said (to his companions), 'Chase and kill him.' So, I killed him." The Prophet (ﷺ) then gave him the belongings of the killed spy (in addition to his share of the war booty).

Sahih al-Bukhari Book 56, Hadith 257 Next Hadith → Ibn `Abbas said, "Thursday! What (great thing) took place on Thursday!" Then he started weeping till his tears wetted the gravels of the ground . Then he said, "On Thursday the illness of Allah's Messenger (ﷺ) was aggravated and he said, "Fetch me writing materials so that I may have something written to you after which you will never go astray." The people (present there) differed in this matter and people should not differ before a prophet. They said, "Allah's Messenger (ﷺ) is seriously sick.' The Prophet (ﷺ) said, "Let me alone, as the state in which I am now, is better than what you are calling me for." The Prophet (ﷺ) on his death-bed, gave three orders saying, "Expel the pagans from the Arabian Peninsula, respect and give gifts to the foreign delegates as you have seen me dealing with them." I forgot the third (order)" (Ya'qub bin Muhammad said, "I asked Al-Mughira bin `Abdur-Rahman about the Arabian Peninsula and he said, 'It comprises Mecca, Medina, Al-Yama-ma and Yemen." Ya'qub added, "And Al-Arj, the beginning of Tihama.")

Sahih al-Bukhari Book 56, Hadith 259