It is narrated from Sayyiduna Ibn Amr (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) delivered a sermon while leaning against the Ka'bah and said: "Muslims are united as one hand against everyone else; the blood of all is equal; even the lowest-ranking Muslim can grant protection to someone."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 6797