The Sunnah of Muhammad (peace and blessings be upon him) and his Sahaba (may Allah be pleased with them)
The messenger of Allah ﷺ said:
«…upon you is my Sunnah, and the Sunnah of the Rightly Guided Caliphs after me»
Source: https://sunnah.com/ibnmajah:42
Sheikh Ul Islam Ibn Taymiyyah رحمه الله authenticates the narration
Source: Majmu’ Al-Fatawa, Volume 20, Page 309
Al-Albani رحمه الله authenticates the hadith, and in the footnotes he says:
”«…The Rightly Guided Caliphs…» and they are the 4 (Abu Bakr, Umar, Uthman, and Ali) رضي الله عنهم"
Source: Sahih Sunan Ibn Majah, Volume 1, Page 31-32
Shu’ayb Al-Arnaaot authenticates the narration
Source: Musnad Al-Imam Ahmed, Volume 28, Page 373
Imam Al-Baghawi رحمه الله says the narration is Hassan (Good). And Shu’ayb Al-Arnaaot (The Muhaqiq) says
that the chain is authentic. And he also quotes Imam Al-Tirmidhi authenticating the hadith.
Source: Sharh Al-Sunnah, Volume 10, Page 205
Sheikh Ul Islam Ibn Taymiyyah رحمه الله authenticates the narration
Source: Majmu’ Al-Fatawa, Volume 20, Page 309
Al-Albani رحمه الله authenticates the hadith, and in the footnotes he says:
”«…The Rightly Guided Caliphs…» and they are the 4 (Abu Bakr, Umar, Uthman, and Ali) رضي الله عنهم"
Source: Sahih Sunan Ibn Majah, Volume 1, Page 31-32
Shu’ayb Al-Arnaaot authenticates the narration
Source: Musnad Al-Imam Ahmed, Volume 28, Page 373
Imam Al-Baghawi رحمه الله says the narration is Hassan (Good). And Shu’ayb Al-Arnaaot (The Muhaqiq) says
that the chain is authentic. And he also quotes Imam Al-Tirmidhi authenticating the hadith.
Source: Sharh Al-Sunnah, Volume 10, Page 205