It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that he used to read "Our hearts are ghuluf" with the heavy reading (muthaqqalah, that is, ghulufun with a dammah on the lam), meaning: containers of wisdom.
He said: "When the Messenger of Allah (peace and blessings be upon him) invited the Jews to learn wisdom, they said: 'How can we learn (more) when our hearts are ghulufun muhkamah (sealed containers)?' That is: they are containers (full) of wisdom."
Only Sulayman bin Arqam (may Allah have mercy on him) narrated this hadith from Imam al-Zuhri (may Allah have mercy on him), and Abbas bin Fadl (may Allah have mercy on him) is alone in narrating it.
Hadith Referenceالمعجم الأوسط / باب العين / 4636
Hadith Gradingمحدثین:إسناده ضعيف جدًّا، فيه سليمان بن أرقم متروك
Hadith Takhrij«قال الهيثمي: فيه سليمان بن أرقم وهو متروك «مجمع الزوائد ومنبع الفوائد، ج 7، ص 154»»