Silsilah as-Sahihah 3383 — Why one Qurayshi equals two non-Qurayshis

It is narrated from Sayyiduna Jubayr bin Mut'im (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The strength of a person from the Quraysh family is twice that of a person from another family." It was said to Zuhri, "On what basis is this?" He said: "On the basis of sound judgment."