From Sahih Bukhari (Hadith 2651):
Narrated Zahdam bin Mudarrib:I heard `Imran bin Husain saying, "The Prophet (ﷺ) said, 'The best people are those living in my generation, then those coming after them, and then those coming after (the second generation)." `Imran said "I do not know whether the Prophet (ﷺ) mentioned two or three generations after your present generation. The Prophet (ﷺ) added, 'There will be some people after you, who will be dishonest and will not be trustworthy and will give witness (evidences) without being asked to give witness, and will vow but will not fulfill their vows, and obesity will appear among them
Reference: Bukhari 2651