Musnad Ahmad 26:413

Azhar ibn Sa‘d narrated to us, Ibn ‘Awn informed us, from Ibrahim, from ‘Ubaydah, from ‘Abdullah, from the Prophet (peace and blessings of Allah be upon him), who said: "The best of people are my generation, those who are next to them, then those who are next to them, then those who are next to them." He said: "And I do not know if he said it a third time or a fourth time." "Then there will come after them a people whose testimony will precede their oath, and their oath will precede their testimony."