(35) باب مَنِ اتَّكَأَ بَيْنَ يَدَىْ أَصْحَابِهِ
Narrated Abu Bakra:
Allah's Messenger (ﷺ) said, "Shall I inform you of the biggest of the great sins?" They said, "Yes, O Allah's Apostle!" He said, "To join partners in worship with Allah, and to be undutiful to one's parents. "
Reference: Sahih al-Bukhari 6273
In-book reference: Book 79, Hadith 47
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 8, Book 74, Hadith 290