It is reported that Al-Sha’bī said, “The only people who used to seek this knowledge were those who combined two characteristics: intelligence and devout worship. If a person was intelligent but not devout, it would be said that only the worshippers can attain this [knowledge], and so he would not try to seek it. And if a person was devout, but not intelligent, it would be said that only the intelligent can attain this [knowledge], and so he would not try to seek it.” Al-Sha’bī continued, “And I fear that today, people who are neither intelligent nor devout try to seek it.”
Ibn Ḥibbān Al-Bustī, Rawḍatu Al-‘Uqalā` wa Nuzhatu Al-Fuḍalā` Vol.1 p9.