When Yaqoub went to Egypt and saw Yousuf and his kingdom he was once looking in his closets when he found a closet full of white papers. He said to Yousuf: "Son, you have changed after me. You have all these papers and you didn’t write one message to send it to me." Yousuf said: "All these papers are for you. Whenever I missed you and longed for you I used to take a paper to write a message to you father but Jibraeel used to prevent me from writing. So I put it in this closet till the closet became as you see now."
Yaqoub asked Jibraeel about that. Jirabeel said: "My Lord prevented me." Yaqoub then asked Allah about it. Allah inspired to him: "It is because you said: "I fear that the wolf would eat him." Didn’t you fear Me? This is your punishment because you feared other than Me."