Isma'il bin Ubayd bin Rifa'ah (may Allah have mercy on him) narrates from his father, from his grandfather, that the Messenger of Allah (peace and blessings be upon him) said to Sayyiduna Umar (may Allah be pleased with him): "Gather your people." So he gathered them near the house of the Messenger of Allah (peace and blessings be upon him), then went in to him and said: O Messenger of Allah, shall I bring them in to you, or will you come out to them? He (peace and blessings be upon him) said: "No, rather I will go out to them myself." So he (peace and blessings be upon him) came to them, stood before them and said: "Is there anyone among you who is not from you?" They said: Yes, among us are our allies, our brothers' sons and our freed slaves. He (peace and blessings be upon him) said: "Our ally is from us, and our brother's son is from us." He said: "You are listening: indeed, my close ones among you are the God-fearing. If you are those, then well and good; otherwise, take care, lest people come with deeds on the Day of Resurrection while you come with burdens, and I turn away from you." Then, while he (peace and blessings be upon him) was standing and they were sitting, he raised both his hands and said: "O people, Quraysh are a people of trust, and whoever seeks stumbles for them, may Allah throw him down on his face." He (peace and blessings be upon him) said this three times.
Hadith Referenceالمعجم الكبير للطبراني / باب الراء / 4530