It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that among the prisoners of Badr, there were some people who had nothing with which to pay ransom. The Prophet (peace and blessings be upon him) fixed their ransom in such a way that they should teach writing to the children of the Ansar. One day, a child came to his father crying. The father asked, "What happened?" He said, "The teacher hit me." He said, "Wicked one! You want to take revenge for Badr. From now on, you will never go to him again."