The Messenger of Allah ﷺ said, "The Muslims are equal in the sanctity of their blood. The lowliest among them may extend protection on behalf of all, and the most distant of them may grant safe conduct binding on the rest. They stand as one hand against all others. Their strong shall return spoils to their weak, and those of them who set out on raids shall share with those who remain behind. No believer shall be killed in retaliation for a disbeliever, nor shall one bound by a covenant be killed while his covenant stands."Ibn Ishaq did not mention retaliation or the equality of blood.
حدثنا قتيبة بن سعيد حدثنا ابن أبي عدي عن ابن إسحق هو محمد ببعض هذا ح و حدثنا عبيد الله بن عمر بن ميسرة حدثني هشيم عن يحيى بن سعيد جميعا
قال رسول الله ﷺ المسلمون تتكافأ دماؤهم يسعى بذمتهم أدناهم ويجير عليهم أقصاهم وهم يد على من سواهم يرد مشدهم على مضعفهم ومتسريهم على قاعدهم لا يقتل مؤمن بكافر ولا ذو عهد في عهده ولم يذكر ابن إسحق القود والتكافؤ
[Hasan] It will come at 4531. Bayhaqi also narrated it at 8/29 from the hadith of Abu Dawud through the same route.Ibn Ishaq stated explicitly that he heard it directly, as recorded by Bayhaqi, and he was corroborated by Yahya bin Saeed, Abdul-Rahman bin Harith, and others.