Bilal bin Sa'd narrates from his father, Sa'd bin Tamim (may Allah be pleased with him), who said: I said: O Messenger of Allah, who are the best of your Ummah? He (peace and blessings be upon him) said: "I and my contemporaries." We said: Then who, O Messenger of Allah? He (peace and blessings be upon him) said: "Then the second generation." I said: Then who, O Messenger of Allah? He (peace and blessings be upon him) said: "Then the third generation." I said: Then who, O Messenger of Allah? He (peace and blessings be upon him) said: "Then there will be people who swear oaths without being asked to swear, who give testimony without being asked to testify, and who are entrusted yet do not fulfil the trust."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5441