Narrated `Abdullah:The Prophet (ﷺ) was asked, "Who are the best people?" He replied: The people of my generation, and then those who will follow (come after) them, and then those who will come after the later; after that there will come some people whose witness will precede their oaths and their oaths will go ahead of their witness." Ibrahim (a sub-narrator) said, "When we were young, our elder friends used to prohibit us from taking oaths by saying, 'I bear witness swearing by Allah, or by Allah's Covenant."'
حَدَّثَنَا سَعْدُ بْنُ حَفْصٍ، حَدَّثَنَا شَيْبَانُ، عَنْ مَنْصُورٍ، عَنْ إِبْرَاهِيمَ، عَنْ عَبِيدَةَ، عَنْ عَبْدِ اللَّهِ، قَالَ سُئِلَ النَّبِيُّ صلى الله عليه وسلم أَىُّ النَّاسِ خَيْرٌ قَالَ " قَرْنِي، ثُمَّ الَّذِينَ يَلُونَهُمْ، ثُمَّ الَّذِينَ يَلُونَهُمْ، ثُمَّ يَجِيءُ قَوْمٌ تَسْبِقُ شَهَادَةُ أَحَدِهِمْ يَمِينَهُ، وَيَمِينُهُ شَهَادَتَهُ ". قَالَ إِبْرَاهِيمُ وَكَانَ أَصْحَابُنَا يَنْهَوْنَا وَنَحْنُ غِلْمَانٌ أَنْ نَحْلِفَ بِالشَّهَادَةِ وَالْعَهْدِ.
Bukhari
Oaths and Vows • Hadith 37