The Messenger of Allah ﷺ said, "The best of people are my generation, then those who follow them, then those who follow them, then those who follow them. Then there will come a people whose oaths outrun their testimony and whose testimony outruns their oaths."
حدثنا هاشم قال حدثنا شيبان عن عاصم عن خيثمة والشعبي
قال رسول الله ﷺ خير الناس قرني ثم الذين يلونهم ثم الذين يلونهم ثم الذين يلونهم ثم يأتي قوم تسبق أيمانهم شهادتهم وشهادتهم أيمانهم
Its isnad is sahih, its narrators are trustworthy and have already been mentioned. Bukhari related the hadith in 5/258, no. 2651, Fath, and Muslim in 4/1916, and it has already come up at 4217. It is a very well-known hadith, one that no book of hadith, whether among the Sahih collections or the Sunan, is without.