Is the hadith, "Do not teach knowledge to the children of the ignoble, and if you do teach them, do not entrust them with positions of authority," authentic, or is there anything in the Prophetic traditions that supports it?

This statement has not been attributed to a Prophetic Hadith. Similar narrations have been reported, but they are weak or fabricated, such as: "Seeking knowledge is an obligation upon every Muslim, and he who places knowledge with those who are unworthy of it is like one who adorns pigs with jewels, pearls, and gold." Students should respect their teacher, thank him, and reward him with supplication and whatever is easy for them, for the Prophet, peace be upon him, said: "Whoever does you a favor, recompense him. If you do not find anything to recompense him with, then supplicate for him until you know that you have recompensed him," and "He who does not thank the people does not thank Allah."