If a teacher cares about what he teaches, his enthusiasm will be evident, exerting a powerful influence on those whom he teaches.
فَيَجِبُ أَنْ يَكُونَ مُقْتَنِعًا بِأَنَّهَا صَحِيحَةٌ وَمُهِمَّةٌ وَنَافِعَةٌ .‏