Hawzah News Agency - Imam al-Ridha (a) says:

صَديقُ كُلِّ امرِئٍ عَقلُهُ وعَدُوُّهُ جَهلُهُ.

‘The friend of every man is his intellect and his enemy is his ignorance.’

al-Kafi, v. ۱, p. ۱۱, no. 4