It was narrated that Jabir bin Samurah said: 'Umar bin Khattab addressed us at Jabiyah and said: “The Messenger of Allah (ﷺ) stood up among us as I stand among you, and said: 'Honor my Companions for my sake, then those who come after them, then those who come after them. Then lying will prevail until a man will give testimony without being asked to do so, and he will swear an oath without being asked to do so.' ”
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْجَرَّاحِ، حَدَّثَنَا جَرِيرٌ، عَنْ عَبْدِ الْمَلِكِ بْنِ عُمَيْرٍ، عَنْ جَابِرِ بْنِ سَمُرَةَ، قَالَ خَطَبَنَا عُمَرُ بْنُ الْخَطَّابِ بِالْجَابِيَةِ فَقَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَامَ فِينَا مِثْلَ مُقَامِي فِيكُمْ فَقَالَ " احْفَظُونِي فِي أَصْحَابِي ثُمَّ الَّذِينَ يَلُونَهُمْ ثُمَّ الَّذِينَ يَلُونَهُمْ ثُمَّ يَفْشُو الْكَذِبُ حَتَّى يَشْهَدَ الرَّجُلُ وَمَا يُسْتَشْهَدُ وَيَحْلِفَ وَمَا يُسْتَحْلَفُ " .
sunnah.com