مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1999
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn "Abbas that the Prophet (ﷺ) said: "No man ever learns anything about astrology but he also learns a branch of witchcraft; whoever learns more (of the former) learns more (of the latter).”
Musnad Ahmad 2000Sahih (Darussalam) []