Hadith 14:23
Narrated Abu Bakra (RA):
The Prophet (ﷺ) considered Shahadah az-Zur (giving false testimony) among the most serious of major sins. [al-Bukhari and Muslim reported it in a long Hadith].
وَعَنْ أَبِي بَكْرَةَ - رضى الله عنه - { عَنِ النَّبِيِّ - صلى الله عليه وسلم -أَنَّهُ عَدَّ شَهَادَةَ اَلزُّورِ فِ ي أَكْبَرِ اَلْكَبَائِرِ } مُتَّفَقٌ عَلَيْهِ فِي حَدِيث ٍ
Original Reference: Bulugh al-Maram 1419