ʿAlī, may Allah be pleased with him, said:
حَدِّثُوا النَّاسَ بِمَا يَعْرِفُونَ (Sahih al-Bukhari: 127)
Translation: Speak to people about what they can understand.
This statement is attributed to ʿAlī. He met the Prophet ﷺ as a believer and died upon faith; he is a ṣaḥābī (صحابی), a Companion.
Notice: The speaker in this example is ʿAlī; do not treat these words as a saying of the Prophet ﷺ.