Who said: "He unfolds knowledge for us, so we know, and withholds it from us, so we do not know," and what does it mean?

This phrase is attributed by some innovators, who are known for lying, to Ali ibn Abi Talib (may Allah be pleased with him). It is necessary to verify the authenticity of the narration before delving into its meaning. The compilers of the Six Books narrated from Abu Juhaifa who said: I asked Ali ibn Abi Talib: "Do you have any knowledge that is not with the people?" He replied: "No, by Allah, we have nothing but what is with the people, except if Allah grants a man understanding of the Quran, or what is in this scroll." In it are the blood money rulings from the Messenger of Allah (peace and blessings be upon him), and that a Muslim should not be killed for a disbeliever.