Clarification of this is in the Hadith of 'Umar bin Al-Khattab, from the Prophet(s.a.w) who said:"The best of people are my generation, then those who follow them,then those who follow them. Then lying will spread, until a man testifies while his testimony was not requested, and a man will take an oath while an oath was not sought

English translation · Jami' at-Tirmidhi