Chapter 78: Good Manners and Form (Al-Adab)
Narrated Anas bin Malik: Allah' s Messenger (ﷺ) mentioned the greatest sins or he was asked about the greatest sins. He said, "To join
partners in worship with Allah; to kill a soul which Allah has forbidden to kill; and to be undutiful or
unkind to one' s parents." The Prophet (ﷺ) added, "Shall I inform you of the biggest of the great sins? That
is the forged statement or the false witness." Shu 'ba (the sub-narrator) states that most probably the
Prophet said, "the false witness."
Sahih al-Bukhari 5977