Saif bin Ubaidullah سيف بن عبيد الله

Name: Saif bin Ubaidullah

Fame: Abu Al-Hasan Al-Sarraj

Kuniya: Abu Al-Hasan

Lineage: Al-Basri, Al-Jarmi

Occupation: Al-Sarraj

Rank: Thiqah

Lived in: Basra, Baghdad

Abu Al-Qasim Al-Tabarani: Thiqah

Abu Bakr Al-Bazzar: Thiqah

Abu Hatim bin Hibban Al-Busti: Rubama Khalaf

Abu Naeem Al-Asbahani: Narrated from Amr bin Yazid Al-Basri that he said: Thiqah

Ibn Hajar Al-Asqalani: Saduq Rubama Khalaf

Al-Dhahabi: Thiqah Salih Mutta'lih

Amr bin Ali Al-Fallas: From the best of creation

Amr bin Yazid Al-Jarmi: Thiqah

Muslimah bin Al-Qasim Al-Andalusi: Feeh Da'eef

Authors of Tahrir Taqrib Al-Tahdhib: Thiqah, his saying Rubama Khalaf, is from Ibn Hibban's own opinion, and only Muslimah weakened him without explaining the reason, so it doesn't stand against those who authenticated him