Narrated 'Abdullah bin 'Amr (RA):
A desert Arab came to the Prophet (ﷺ) and said, "O Allah's Messenger, what are the major sins?" The narrator reported the Hadith and it contains: "The false oath." It contains also: I asked, "What is the false oath?" The Prophet (ﷺ) replied, "It is that (oath) by which one takes possession of the property of a Muslim person, while he is lying." [al-Bukhari reported it]. (DE)
Reference (DE): Bulugh al-Maram 1380 (DE)
In-book reference (DE): Book 13, Hadith 7 (DE)
English translation (DE): Book 13, Hadith 1380 (DE)