Abu Dawud said, “I heard Ahmad (ibn Hanbal) remark, ‘Ibn Ishaq was passionate about hadith; he would take other people’s notebooks and incorporate them into his own.’

I (the author) say: Such a procedure is allowed; al-Bukhari’s Sahih, for instance, contains many suspended (muʿallaq) narrations.

Ahmad also said, “I prefer Ibn Ishaq to Musa ibn ʿUbaydah.”

I add: Musa was deemed weak.

Ahmad continued, “Ibn Ishaq practiced tadlis (ambiguous attribution); yet with the notebook of Ibrahim ibn Saʿd, if he had actually heard the report he would say, ‘He narrated to me,’ and if he had not, he would say, ‘So-and-so said.’”

Ahmad further stated, “When Ibn Ishaq arrived in Baghdad he did not care whom he quoted—al-Kalbi or anyone else—and he said, ‘He is not authoritative.’”

Abu al-ʿAbbas ibn ʿUqda said, “I heard ʿAbd Allah ibn Ahmad ibn Hanbal report: ‘My father would pursue Ibn Ishaq’s narrations, writing them down copiously with both high and low chains and including them in the Musnad, yet I never saw him retain those hadith permanently.’

He was asked, ‘Can his reports be cited as evidence?’

He replied, ‘They were not used as proof in the Sunan.’”

Ayyub ibn Ishaq ibn Saferi (1) said, “I asked Ahmad ibn Hanbal, ‘If Ibn Ishaq is the sole transmitter of a hadith, will you accept it?’

He answered, ‘By Allah, no. I saw him relate a single report from several people without separating one person’s words from another’s.’”

He added, “As for ʿAli ibn al-Madini, he used to commend him and give him precedence.”

Muhammad ibn ʿUthman al-ʿAbsi narrated from ʿAli, ‘He is sound, of middling rank.’

Ibn Abi Khaythamah transmitted from Yahya, ‘There is no harm in him.’ On another occasion he said, ‘He is not that strong.’ I heard